diff --git a/LehrerApp.Desktop.Tests/CreateLetterDialogViewModelTests.cs b/LehrerApp.Desktop.Tests/CreateLetterDialogViewModelTests.cs
index 391d7ee..d0b86b6 100644
--- a/LehrerApp.Desktop.Tests/CreateLetterDialogViewModelTests.cs
+++ b/LehrerApp.Desktop.Tests/CreateLetterDialogViewModelTests.cs
@@ -41,6 +41,19 @@ public sealed class CreateLetterDialogViewModelTests : IDisposable
         Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
     }
 
+    [Fact]
+    public void KonstanterPflichttext_BenoetigtKeineExterneEingabe()
+    {
+        var store = StoreWithTemplate(new PlaceholderDefinition("Brieftext", PlaceholderType.Multiline,
+            Required: true, IsConstant: true, ConstantValue: "Fest im Vorlagenpaket"));
+        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), store);
+        var output = Path.Combine(_directory, "Konstant.pdf");
+
+        Assert.True(vm.CanGenerate);
+        Assert.True(vm.Generate(output));
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
+    }
+
     private CreateLetterDialogViewModel Build(Student student, TemplateStore store) =>
         new(student, store, new QuestTemplateRenderer(), new FakeMemberships([]), new FakeGroups([]));
 
diff --git a/LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.LetterTemplates.cs b/LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.LetterTemplates.cs
index 20454b4..9915a09 100644
--- a/LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.LetterTemplates.cs
+++ b/LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.LetterTemplates.cs
@@ -54,8 +54,8 @@ public partial class SettingsViewModel
     private LetterTemplateListItem CreateItem(InstalledTemplate template)
     {
         var loaded = _letterTemplates.Load(template);
-        return new(template, loaded.Manifest.SchemaVersion, loaded.Manifest.Placeholders.Count,
-            loaded.Manifest.Placeholders.Count(x => x.Required));
+        return new(template, loaded.Manifest.SchemaVersion, loaded.Manifest.Placeholders.Count(x => !x.IsConstant),
+            loaded.Manifest.Placeholders.Count(x => !x.IsConstant && x.Required));
     }
 }
 
diff --git a/LehrerApp.Desktop/ViewModels/Students/CreateLetterDialogViewModel.cs b/LehrerApp.Desktop/ViewModels/Students/CreateLetterDialogViewModel.cs
index 560c709..b4723cf 100644
--- a/LehrerApp.Desktop/ViewModels/Students/CreateLetterDialogViewModel.cs
+++ b/LehrerApp.Desktop/ViewModels/Students/CreateLetterDialogViewModel.cs
@@ -77,7 +77,8 @@ public partial class CreateLetterDialogViewModel : ObservableObject
                 var loaded = _templates.Load(SelectedTemplate.Model); var values = BuildValues();
                 var validation = new TemplateLoader().Validate(loaded, values.ToDictionary(x => x.Key, x => x.Value.Type));
                 foreach (var issue in validation.Issues) Issues.Add(new(issue.Message, issue.Severity == ValidationSeverity.Error));
-                foreach (var required in loaded.Manifest.Placeholders.Where(x => x.Required && values.TryGetValue(x.Name, out var value) && IsEmpty(value)))
+                foreach (var required in loaded.Manifest.Placeholders.Where(x => !x.IsConstant && x.Required
+                             && values.TryGetValue(x.Name, out var value) && IsEmpty(value)))
                     Issues.Add(new($"Für das Pflichtfeld „{required.Name}“ ist kein Wert vorhanden.", true));
             }
             catch (Exception ex) when (ex is IOException or InvalidDataException or TemplateValidationException)
diff --git a/LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs b/LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs
index ef0ee59..593a794 100644
--- a/LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs
+++ b/LehrerApp.TemplateDesigner.Tests/ProjectLifecycleTests.cs
@@ -53,6 +53,10 @@ public sealed class ProjectLifecycleTests
         placeholder.Type = LehrerApp.Templating.PlaceholderType.Text;
         placeholder.Required = true;
         placeholder.Sample = "Deutsch";
+        placeholder.IsConstant = true;
+        placeholder.Bold = true;
+        placeholder.Italic = true;
+        placeholder.Underline = true;
 
         Assert.Same(placeholder, viewModel.SelectedPlaceholder);
         Assert.True(viewModel.HasSelectedPlaceholder);
@@ -61,6 +65,11 @@ public sealed class ProjectLifecycleTests
         Assert.Equal("Sprache", definition.Name);
         Assert.Equal(LehrerApp.Templating.PlaceholderType.Text, definition.Type);
         Assert.True(definition.Required);
+        Assert.True(definition.IsConstant);
+        Assert.Equal("Deutsch", definition.ConstantValue);
+        Assert.True(definition.Bold);
+        Assert.True(definition.Italic);
+        Assert.True(definition.Underline);
 
         viewModel.RemoveSelectedPlaceholder();
         Assert.Empty(viewModel.Placeholders);
diff --git a/LehrerApp.TemplateDesigner/DesignerViewModel.cs b/LehrerApp.TemplateDesigner/DesignerViewModel.cs
index 5b75859..c302fcd 100644
--- a/LehrerApp.TemplateDesigner/DesignerViewModel.cs
+++ b/LehrerApp.TemplateDesigner/DesignerViewModel.cs
@@ -109,6 +109,8 @@ public partial class DesignerViewModel : ObservableObject
             issues.Add(new(ValidationSeverity.Error, $"Platzhalter „{used}“ ist nicht deklariert."));
         foreach (var path in layout.Elements.Select(x => x switch { BackgroundElement b => b.Path, ImageElement i => i.Path, _ => null }).Where(x => x is not null))
             if (!Assets.ContainsKey(path!)) issues.Add(new(ValidationSeverity.Error, $"Asset „{path}“ fehlt."));
+        foreach (var issue in TemplateDataResolver.ValidateConstants(manifest))
+            issues.Add(new(ValidationSeverity.Error, issue));
         if (issues.Count > 0) throw new TemplateValidationException(new(issues));
         return new(manifest, layout, new Dictionary<string, byte[]>(Assets));
     }
@@ -145,7 +147,9 @@ public partial class DesignerViewModel : ObservableObject
         SelectedMetadata = null;
         Placeholders.Clear();
         foreach (var placeholder in template.Manifest.Placeholders)
-            Placeholders.Add(new(placeholder.Name, placeholder.Type, placeholder.Required, DesignerPlaceholder.SampleFor(placeholder.Type)));
+            Placeholders.Add(new(placeholder.Name, placeholder.Type, placeholder.Required,
+                placeholder.IsConstant ? placeholder.ConstantValue ?? "" : DesignerPlaceholder.SampleFor(placeholder.Type),
+                placeholder.IsConstant, placeholder.Bold, placeholder.Italic, placeholder.Underline));
         SelectedPlaceholder = Placeholders.FirstOrDefault();
         Assets.Clear(); AssetItems.Clear();
         foreach (var asset in template.Assets) AddOrReplaceAsset(asset.Key, asset.Value, keepName: true);
@@ -201,7 +205,9 @@ public partial class DesignerViewModel : ObservableObject
             var name = placeholder.Name.Trim();
             if (name.Length == 0) throw new InvalidDataException("Ein Platzhaltername darf nicht leer sein.");
             if (!names.Add(name)) throw new InvalidDataException($"Platzhalter „{name}“ ist mehrfach definiert.");
-            result.Add(new(name, placeholder.Type, placeholder.Required));
+            result.Add(new(name, placeholder.Type, placeholder.Required, placeholder.IsConstant,
+                placeholder.IsConstant ? placeholder.Sample : null,
+                placeholder.Bold, placeholder.Italic, placeholder.Underline));
         }
         return result;
     }
@@ -439,8 +445,29 @@ public partial class DesignerPlaceholder : ObservableObject
     [ObservableProperty] private PlaceholderType _type;
     [ObservableProperty] private bool _required;
     [ObservableProperty] private string _sample;
-    public DesignerPlaceholder(string name, PlaceholderType type, bool required, string sample)
-    { _name = name; _type = type; _required = required; _sample = sample; }
+    [ObservableProperty] private bool _isConstant;
+    [ObservableProperty] private bool _bold;
+    [ObservableProperty] private bool _italic;
+    [ObservableProperty] private bool _underline;
+    public bool SupportsConstantValue => Type is PlaceholderType.Text or PlaceholderType.Multiline
+        or PlaceholderType.Date or PlaceholderType.Number;
+    public bool SupportsRichText => IsConstant && Type is PlaceholderType.Text or PlaceholderType.Multiline;
+
+    public DesignerPlaceholder(string name, PlaceholderType type, bool required, string sample,
+        bool isConstant = false, bool bold = false, bool italic = false, bool underline = false)
+    {
+        _name = name; _type = type; _required = required; _sample = sample;
+        _isConstant = isConstant; _bold = bold; _italic = italic; _underline = underline;
+    }
+
+    partial void OnTypeChanged(PlaceholderType value)
+    {
+        OnPropertyChanged(nameof(SupportsConstantValue));
+        OnPropertyChanged(nameof(SupportsRichText));
+        if (!SupportsConstantValue) IsConstant = false;
+    }
+
+    partial void OnIsConstantChanged(bool value) => OnPropertyChanged(nameof(SupportsRichText));
 
     public PlaceholderValue ToValue() => Type switch
     {
diff --git a/LehrerApp.TemplateDesigner/MainWindow.axaml b/LehrerApp.TemplateDesigner/MainWindow.axaml
index fa2494a..217b538 100644
--- a/LehrerApp.TemplateDesigner/MainWindow.axaml
+++ b/LehrerApp.TemplateDesigner/MainWindow.axaml
@@ -113,9 +113,33 @@
                     <ComboBox ItemsSource="{Binding PlaceholderTypes}" SelectedItem="{Binding SelectedPlaceholder.Type, Mode=TwoWay}"/></StackPanel>
                 </Grid>
                 <CheckBox Content="Pflichtwert" IsChecked="{Binding SelectedPlaceholder.Required, Mode=TwoWay}"/>
-                <StackPanel><TextBlock Text="Beispielwert für die Vorschau" Classes="label"/>
-                  <TextBox Text="{Binding SelectedPlaceholder.Sample, Mode=TwoWay}" AcceptsReturn="True"
+                <CheckBox IsChecked="{Binding SelectedPlaceholder.IsConstant, Mode=TwoWay}"
+                          IsEnabled="{Binding SelectedPlaceholder.SupportsConstantValue}">
+                  <TextBlock Text="Beispielwert fest im Paket verwenden (konstant, extern nicht überschreibbar)"
+                             TextWrapping="Wrap"/>
+                </CheckBox>
+                <StackPanel><TextBlock Text="Beispielwert / konstanter Paketwert" Classes="label"/>
+                  <StackPanel Orientation="Horizontal" Spacing="6" Margin="0,3,0,5">
+                    <Button Content="F" FontWeight="Bold" Padding="10,3" Click="OnBoldSelection"
+                            IsEnabled="{Binding SelectedPlaceholder.SupportsRichText}" ToolTip.Tip="Markierten Text fett setzen"/>
+                    <Button Content="K" FontStyle="Italic" Padding="10,3" Click="OnItalicSelection"
+                            IsEnabled="{Binding SelectedPlaceholder.SupportsRichText}" ToolTip.Tip="Markierten Text kursiv setzen"/>
+                    <Button Content="U̲" Padding="10,3" Click="OnUnderlineSelection"
+                            IsEnabled="{Binding SelectedPlaceholder.SupportsRichText}" ToolTip.Tip="Markierten Text unterstreichen"/>
+                  </StackPanel>
+                  <TextBox x:Name="PlaceholderValueTextBox" Text="{Binding SelectedPlaceholder.Sample, Mode=TwoWay}" AcceptsReturn="True"
                            MinHeight="68" MaxHeight="120" TextWrapping="Wrap" PlaceholderText="Beispieldaten eingeben"/></StackPanel>
+                <TextBlock IsVisible="{Binding SelectedPlaceholder.SupportsRichText}"
+                           Text="Externe Werte im Text: ${Student.LastName}. Markup: [b]fett[/b], [i]kursiv[/i], [u]unterstrichen[/u]."
+                           FontSize="11" Opacity="0.65" TextWrapping="Wrap"/>
+                <StackPanel>
+                  <TextBlock Text="Hervorhebung bei direkter Verwendung in TEXT/TEXTBOX" Classes="label"/>
+                  <StackPanel Orientation="Horizontal" Spacing="14">
+                    <CheckBox Content="Fett" IsChecked="{Binding SelectedPlaceholder.Bold, Mode=TwoWay}"/>
+                    <CheckBox Content="Kursiv" IsChecked="{Binding SelectedPlaceholder.Italic, Mode=TwoWay}"/>
+                    <CheckBox Content="Unterstrichen" IsChecked="{Binding SelectedPlaceholder.Underline, Mode=TwoWay}"/>
+                  </StackPanel>
+                </StackPanel>
                 <Button Content="Platzhalter entfernen" HorizontalAlignment="Left" Click="OnRemovePlaceholder"/>
               </StackPanel>
             </Border>
diff --git a/LehrerApp.TemplateDesigner/MainWindow.axaml.cs b/LehrerApp.TemplateDesigner/MainWindow.axaml.cs
index 30671fd..b8accb6 100644
--- a/LehrerApp.TemplateDesigner/MainWindow.axaml.cs
+++ b/LehrerApp.TemplateDesigner/MainWindow.axaml.cs
@@ -39,6 +39,23 @@ public partial class MainWindow : Window
         _viewModel.MetadataItems.Remove(selected); _viewModel.SelectedMetadata = null; _viewModel.CanExport = false;
     }
     private void OnRemovePlaceholder(object? sender, RoutedEventArgs e) => _viewModel.RemoveSelectedPlaceholder();
+    private void OnBoldSelection(object? sender, RoutedEventArgs e) => WrapPlaceholderSelection("[b]", "[/b]");
+    private void OnItalicSelection(object? sender, RoutedEventArgs e) => WrapPlaceholderSelection("[i]", "[/i]");
+    private void OnUnderlineSelection(object? sender, RoutedEventArgs e) => WrapPlaceholderSelection("[u]", "[/u]");
+
+    private void WrapPlaceholderSelection(string opening, string closing)
+    {
+        if (_viewModel.SelectedPlaceholder is not { SupportsRichText: true } placeholder
+            || this.FindControl<TextBox>("PlaceholderValueTextBox") is not { } editor) return;
+        var source = editor.Text ?? "";
+        var start = Math.Min(editor.SelectionStart, editor.SelectionEnd);
+        var end = Math.Max(editor.SelectionStart, editor.SelectionEnd);
+        var updated = source[..start] + opening + source[start..end] + closing + source[end..];
+        placeholder.Sample = updated; editor.Text = updated;
+        editor.SelectionStart = start + opening.Length;
+        editor.SelectionEnd = end + opening.Length;
+        editor.Focus(); _viewModel.CanExport = false;
+    }
     private void OnAddElement(object? sender, RoutedEventArgs e)
     { try { _viewModel.AddElement(); } catch (Exception ex) { _viewModel.SetStatus(ex.Message, true); } }
     private void OnMeasureOverlayMode(object? sender, RoutedEventArgs e)
diff --git a/LehrerApp.TemplateDesigner/StarterTemplateLibrary.cs b/LehrerApp.TemplateDesigner/StarterTemplateLibrary.cs
index 437c2a7..4b4dcb9 100644
--- a/LehrerApp.TemplateDesigner/StarterTemplateLibrary.cs
+++ b/LehrerApp.TemplateDesigner/StarterTemplateLibrary.cs
@@ -110,7 +110,8 @@ public sealed class StarterTemplateLibrary
         LayoutFile = source.LayoutFile,
         MetadataFile = source.MetadataFile,
         Metadata = new(source.Metadata, StringComparer.OrdinalIgnoreCase),
-        Placeholders = source.Placeholders.Select(x => new PlaceholderDefinition(x.Name, x.Type, x.Required)).ToList(),
+        Placeholders = source.Placeholders.Select(x => new PlaceholderDefinition(x.Name, x.Type, x.Required,
+            x.IsConstant, x.ConstantValue, x.Bold, x.Italic, x.Underline)).ToList(),
     };
 
     private static StarterTemplateItem ToItem(TemplateManifest manifest, string path) =>
diff --git a/LehrerApp.Templating.Tests/ConstantPlaceholderTests.cs b/LehrerApp.Templating.Tests/ConstantPlaceholderTests.cs
new file mode 100644
index 0000000..a6a5361
--- /dev/null
+++ b/LehrerApp.Templating.Tests/ConstantPlaceholderTests.cs
@@ -0,0 +1,144 @@
+using LehrerApp.Templating;
+using Xunit;
+
+namespace LehrerApp.Templating.Tests;
+
+public sealed class ConstantPlaceholderTests
+{
+    [Fact]
+    public void Resolver_KonstanterWertUeberschreibtExternenWert()
+    {
+        var manifest = new TemplateManifest
+        {
+            Placeholders = [new("Hinweis", PlaceholderType.Multiline, true, true, "Interner Langtext")],
+        };
+        var external = new Dictionary<string, PlaceholderValue>
+        { ["Hinweis"] = new MultilineValue("Extern manipuliert") };
+
+        var resolved = TemplateDataResolver.Resolve(manifest, external);
+
+        Assert.Equal("Interner Langtext", Assert.IsType<MultilineValue>(resolved["Hinweis"]).Value);
+    }
+
+    [Fact]
+    public void Renderer_BenoetigtFuerKonstantenPflichtwertKeineExternenDatenUndUnterstuetztHervorhebung()
+    {
+        var manifest = new TemplateManifest
+        {
+            Id = "konstant", Name = "Konstant",
+            Placeholders = [new("Hinweis", PlaceholderType.Multiline, true, true,
+                "Dieser Text lebt im Paket.", Bold: true, Italic: true, Underline: true)],
+        };
+        var layout = new LayoutParser().Parse("PAGE 210 297 mm\nTEXTBOX 20 20 170 50 $Hinweis size=11");
+        var template = new LoadedTemplate(manifest, layout, new Dictionary<string, byte[]>());
+
+        var pdf = new QuestTemplateRenderer().RenderToPdf(template, new EmptyProvider());
+
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(pdf, 0, 4));
+    }
+
+    [Fact]
+    public void Validate_BehandeltKonstantenPflichtwertAlsInternErfuellt()
+    {
+        var manifest = new TemplateManifest
+        {
+            Placeholders =
+            [
+                new("Intern", PlaceholderType.Text, true, true, "Fest"),
+                new("Extern", PlaceholderType.Text, true),
+            ],
+        };
+        var template = new LoadedTemplate(manifest, new(210, 297, "mm", []), new Dictionary<string, byte[]>());
+
+        var result = new TemplateLoader().Validate(template, new Dictionary<string, PlaceholderType>());
+
+        Assert.Single(result.Issues);
+        Assert.Contains("Extern", result.Issues[0].Message);
+    }
+
+    [Fact]
+    public void PaketRoundtrip_BehaeltKonstantenWertUndTextformatierung()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"constant-{Guid.NewGuid():N}.lavorlage");
+        try
+        {
+            var manifest = new TemplateManifest
+            {
+                Id = "konstant", Name = "Konstant",
+                Placeholders = [new("Baustein", PlaceholderType.Text, false, true, "Fest im Paket",
+                    Bold: true, Italic: false, Underline: true)],
+            };
+            TemplatePackage.Create(path, manifest, "PAGE 210 297 mm\nTEXT 20 20 $Baustein",
+                new Dictionary<string, byte[]>());
+
+            var definition = Assert.Single(new TemplateLoader().LoadFromPackage(path).Manifest.Placeholders);
+
+            Assert.True(definition.IsConstant);
+            Assert.Equal("Fest im Paket", definition.ConstantValue);
+            Assert.True(definition.Bold);
+            Assert.True(definition.Underline);
+        }
+        finally { if (File.Exists(path)) File.Delete(path); }
+    }
+
+    [Fact]
+    public void RichTextParser_UnterstuetztVerschachtelteHervorhebungUndExternePlatzhalter()
+    {
+        var runs = TemplateRichText.Parse("Hallo [b]Familie [i]${Student.LastName}[/i][/b]!");
+
+        var placeholder = Assert.Single(runs, x => x.IsPlaceholder);
+        Assert.Equal("Student.LastName", placeholder.Placeholder);
+        Assert.True(placeholder.Bold);
+        Assert.True(placeholder.Italic);
+        Assert.False(placeholder.Underline);
+        Assert.Throws<InvalidDataException>(() => TemplateRichText.Parse("[b]nicht geschlossen"));
+    }
+
+    [Fact]
+    public void ExternerWertWirdImKonstantenRichTextNichtAlsMarkupInterpretiert()
+    {
+        var manifest = new TemplateManifest
+        {
+            Id = "sicher", Name = "Sicher",
+            Placeholders =
+            [
+                new("Baustein", PlaceholderType.Multiline, true, true,
+                    "Sehr geehrte Familie [b]${Student.LastName}[/b],"),
+                new("Student.LastName", PlaceholderType.Text, true),
+            ],
+        };
+        var template = new LoadedTemplate(manifest,
+            new LayoutParser().Parse("PAGE 210 297 mm\nTEXTBOX 20 20 170 50 $Baustein"),
+            new Dictionary<string, byte[]>());
+        var provider = new ValuesProvider(new Dictionary<string, PlaceholderValue>
+        { ["Student.LastName"] = new TextValue("[u]nicht als Markup geöffnet") });
+
+        var pdf = new QuestTemplateRenderer().RenderToPdf(template, provider);
+
+        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(pdf, 0, 4));
+    }
+
+    [Fact]
+    public void KonstantenValidierung_MeldetNichtDeklarierteEingebettetePlatzhalter()
+    {
+        var manifest = new TemplateManifest
+        {
+            Placeholders = [new("Baustein", PlaceholderType.Text, false, true, "Hallo ${Unbekannt}")],
+        };
+
+        var issue = Assert.Single(TemplateDataResolver.ValidateConstants(manifest));
+
+        Assert.Contains("Unbekannt", issue);
+    }
+
+    private sealed class EmptyProvider : ITemplateDataProvider
+    {
+        public IReadOnlyDictionary<string, PlaceholderValue> GetValues() =>
+            new Dictionary<string, PlaceholderValue>();
+    }
+
+    private sealed class ValuesProvider(IReadOnlyDictionary<string, PlaceholderValue> values) : ITemplateDataProvider
+    {
+        public IReadOnlyDictionary<string, PlaceholderValue> GetValues() => values;
+    }
+}
diff --git a/LehrerApp.Templating/Model.cs b/LehrerApp.Templating/Model.cs
index c53d00f..5b98bc5 100644
--- a/LehrerApp.Templating/Model.cs
+++ b/LehrerApp.Templating/Model.cs
@@ -23,7 +23,9 @@ public interface ITemplateDataProvider
 }
 
 public sealed record PageSizeDefinition(float Width, float Height, string Unit = "mm");
-public sealed record PlaceholderDefinition(string Name, PlaceholderType Type, bool Required = false);
+public sealed record PlaceholderDefinition(string Name, PlaceholderType Type, bool Required = false,
+    bool IsConstant = false, string? ConstantValue = null,
+    bool Bold = false, bool Italic = false, bool Underline = false);
 
 public sealed class TemplateManifest
 {
diff --git a/LehrerApp.Templating/QuestTemplateRenderer.cs b/LehrerApp.Templating/QuestTemplateRenderer.cs
index cb84511..25b8238 100644
--- a/LehrerApp.Templating/QuestTemplateRenderer.cs
+++ b/LehrerApp.Templating/QuestTemplateRenderer.cs
@@ -23,7 +23,7 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
     private static IReadOnlyDictionary<string, PlaceholderValue> ValidateData(LoadedTemplate template,
         ITemplateDataProvider provider)
     {
-        var values = provider.GetValues();
+        var values = TemplateDataResolver.Resolve(template.Manifest, provider.GetValues());
         var validation = new TemplateLoader().Validate(template, values.ToDictionary(x => x.Key, x => x.Value.Type));
         if (!validation.IsValid) throw new TemplateValidationException(validation);
         return values;
@@ -71,11 +71,12 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
                     .TranslateY(UnitConverter.Points(text.Y, unit))
                     .Width(UnitConverter.Points(Math.Max(0, template.Layout.Width - text.X), unit))
                     .Height(QuestTemplateRenderer.ParseFloat(text.Attributes, "size", 11) * 1.8f);
-                RenderText(textContainer, ResolveContent(text.Content, text.Placeholder, text.Format, values), text.Attributes);
+                RenderResolvedText(textContainer, text.Content, text.Placeholder, text.Format,
+                    values, template.Manifest, text.Attributes);
                 break;
             case TextBoxElement box:
-                RenderText(Position(root, box, unit).Shrink(),
-                    ResolveContent(box.Content, box.Placeholder, box.Format, values), box.Attributes);
+                RenderResolvedText(Position(root, box, unit).Shrink(), box.Content, box.Placeholder, box.Format,
+                    values, template.Manifest, box.Attributes);
                 break;
             case TableElement table:
                 if (values.GetValueOrDefault(table.Placeholder) is TableValue tableValue)
@@ -104,9 +105,63 @@ public sealed class QuestTemplateRenderer : ITemplateRenderer, ITemplatePreviewR
         descriptor.FontSize(ParseFloat(attributes, "size", 11));
         if (ParseBool(attributes, "bold")) descriptor.SemiBold();
         if (ParseBool(attributes, "italic")) descriptor.Italic();
+        if (ParseBool(attributes, "underline")) descriptor.Underline();
         if (attributes.TryGetValue("color", out var color)) descriptor.FontColor(color);
     }
 
+    private static void RenderResolvedText(IContainer container, string content, string? placeholder, string? format,
+        IReadOnlyDictionary<string, PlaceholderValue> values, TemplateManifest manifest,
+        IReadOnlyDictionary<string, string> elementAttributes)
+    {
+        var attributes = TextAttributes(manifest, placeholder, elementAttributes);
+        var definition = placeholder is null ? null
+            : manifest.Placeholders.FirstOrDefault(x => x.Name.Equals(placeholder, StringComparison.Ordinal));
+        if (definition is { IsConstant: true, Type: PlaceholderType.Text or PlaceholderType.Multiline })
+        {
+            RenderRichText(container, TemplateRichText.Parse(definition.ConstantValue ?? ""), values, attributes);
+            return;
+        }
+        RenderText(container, ResolveContent(content, placeholder, format, values), attributes);
+    }
+
+    private static void RenderRichText(IContainer container, IReadOnlyList<TemplateRichTextRun> runs,
+        IReadOnlyDictionary<string, PlaceholderValue> values, IReadOnlyDictionary<string, string> attributes)
+    {
+        var aligned = attributes.GetValueOrDefault("align", "left").ToLowerInvariant() switch
+        { "center" => container.AlignCenter(), "right" => container.AlignRight(), _ => container.AlignLeft() };
+        var fontSize = ParseFloat(attributes, "size", 11);
+        var globalBold = ParseBool(attributes, "bold");
+        var globalItalic = ParseBool(attributes, "italic");
+        var globalUnderline = ParseBool(attributes, "underline");
+        attributes.TryGetValue("color", out var color);
+        aligned.Text(text =>
+        {
+            foreach (var run in runs)
+            {
+                var content = run.Placeholder is null ? run.Text
+                    : values.TryGetValue(run.Placeholder, out var value) ? Format(value, run.Format) : "";
+                var span = text.Span(content).FontSize(fontSize);
+                if (globalBold || run.Bold) span.SemiBold();
+                if (globalItalic || run.Italic) span.Italic();
+                if (globalUnderline || run.Underline) span.Underline();
+                if (color is not null) span.FontColor(color);
+            }
+        });
+    }
+
+    private static IReadOnlyDictionary<string, string> TextAttributes(TemplateManifest manifest, string? placeholder,
+        IReadOnlyDictionary<string, string> elementAttributes)
+    {
+        if (placeholder is null) return elementAttributes;
+        var definition = manifest.Placeholders.FirstOrDefault(x => x.Name.Equals(placeholder, StringComparison.Ordinal));
+        if (definition is null || (!definition.Bold && !definition.Italic && !definition.Underline)) return elementAttributes;
+        var result = new Dictionary<string, string>(elementAttributes, StringComparer.OrdinalIgnoreCase);
+        if (definition.Bold) result["bold"] = "true";
+        if (definition.Italic) result["italic"] = "true";
+        if (definition.Underline) result["underline"] = "true";
+        return result;
+    }
+
     private static string ResolveContent(string content, string? placeholder, string? format,
         IReadOnlyDictionary<string, PlaceholderValue> values)
     {
diff --git a/LehrerApp.Templating/README.md b/LehrerApp.Templating/README.md
index 749dc0a..10904a5 100644
--- a/LehrerApp.Templating/README.md
+++ b/LehrerApp.Templating/README.md
@@ -1,5 +1,43 @@
 # LehrerApp Templating
 
+## Konstante Platzhalter und Hervorhebung
+
+Ein Platzhalter kann seinen Wert vollständig im Vorlagenpaket tragen. `IsConstant=true` bewirkt,
+dass `ConstantValue` beim Rendern immer verwendet wird; ein gleichnamiger Wert aus dem externen
+`ITemplateDataProvider` wird bewusst ignoriert. Damit eignen sich Konstanten besonders für lange
+Textbausteine in `TEXTBOX`, rechtliche Hinweise oder wiederkehrende Fußtexte.
+
+```csharp
+new PlaceholderDefinition(
+    "Datenschutzhinweis",
+    PlaceholderType.Multiline,
+    IsConstant: true,
+    ConstantValue: "Dieser längere Text wird im Paket gespeichert.",
+    Bold: true,
+    Italic: false,
+    Underline: false);
+```
+
+Konstante Werte werden für `Text`, `Multiline`, `Date` und `Number` unterstützt. Die Eigenschaften
+`Bold`, `Italic` und `Underline` wirken, wenn der Platzhalter direkt von einem `TEXT`- oder
+`TEXTBOX`-Element referenziert wird. In der Layout-DSL kann Unterstreichung außerdem direkt mit
+`underline=true` gesetzt werden.
+
+Konstante Text- und Multiline-Werte unterstützen zusätzlich abschnittsweise Hervorhebung und
+eingebettete externe Platzhalter:
+
+```text
+Sehr geehrte Familie [b]${Student.LastName}[/b],
+
+bitte geben Sie die [u]unterschriebene Erklärung[/u] bis [i]Freitag[/i] zurück.
+```
+
+Unterstützt werden `[b]…[/b]`, `[i]…[/i]` und `[u]…[/u]`, auch verschachtelt. Die Klammerform
+`${Name}` ist in Fließtext vorzuziehen; `${Datum|dd.MM.yyyy}` erlaubt zusätzlich ein Format.
+Eingebettete Platzhalter müssen im Manifest als externe Platzhalter deklariert sein. Ihre gelieferten
+Werte werden immer als reiner Text behandelt und können deshalb kein Markup einschleusen. Mit
+`\[`, `\$` und `\\` lassen sich die Steuerzeichen wörtlich ausgeben.
+
 ## Freie Paketmetadaten
 
 Jedes neu gespeicherte `.lavorlage`-Paket enthält eine lesbare `metadata.txt`. Pro Zeile steht ein
diff --git a/LehrerApp.Templating/TemplateDataResolver.cs b/LehrerApp.Templating/TemplateDataResolver.cs
new file mode 100644
index 0000000..ad47270
--- /dev/null
+++ b/LehrerApp.Templating/TemplateDataResolver.cs
@@ -0,0 +1,73 @@
+using System.Globalization;
+
+namespace LehrerApp.Templating;
+
+public static class TemplateDataResolver
+{
+    public static IReadOnlyList<string> ValidateConstants(TemplateManifest manifest)
+    {
+        var issues = new List<string>();
+        var definitions = manifest.Placeholders.GroupBy(x => x.Name, StringComparer.Ordinal)
+            .ToDictionary(x => x.Key, x => x.First(), StringComparer.Ordinal);
+        foreach (var constant in manifest.Placeholders.Where(x => x.IsConstant))
+        {
+            try
+            {
+                ConstantValue(constant);
+                if (constant.Type is not (PlaceholderType.Text or PlaceholderType.Multiline)) continue;
+                foreach (var reference in TemplateRichText.UsedPlaceholders(constant.ConstantValue ?? ""))
+                {
+                    if (!definitions.TryGetValue(reference, out var target))
+                        issues.Add($"Konstanter Text „{constant.Name}“ verwendet den nicht deklarierten Platzhalter „{reference}“.");
+                    else if (target.IsConstant)
+                        issues.Add($"Konstanter Text „{constant.Name}“ darf nur externe Platzhalter verwenden; „{reference}“ ist ebenfalls konstant.");
+                    else if (target.Type is not (PlaceholderType.Text or PlaceholderType.Multiline
+                                 or PlaceholderType.Date or PlaceholderType.Number))
+                        issues.Add($"Eingebetteter Platzhalter „{reference}“ hat keinen textuell darstellbaren Typ.");
+                }
+            }
+            catch (InvalidDataException ex) { issues.Add(ex.Message); }
+        }
+        return issues;
+    }
+
+    public static IReadOnlyDictionary<string, PlaceholderValue> Resolve(TemplateManifest manifest,
+        IReadOnlyDictionary<string, PlaceholderValue> externalValues)
+    {
+        var result = new Dictionary<string, PlaceholderValue>(externalValues, StringComparer.Ordinal);
+        foreach (var definition in manifest.Placeholders.Where(x => x.IsConstant))
+            result[definition.Name] = ConstantValue(definition);
+        return result;
+    }
+
+    public static PlaceholderValue ConstantValue(PlaceholderDefinition definition)
+    {
+        var raw = definition.ConstantValue ?? "";
+        return definition.Type switch
+        {
+            PlaceholderType.Text => new TextValue(raw),
+            PlaceholderType.Multiline => new MultilineValue(raw),
+            PlaceholderType.Date => new DateValue(ParseDate(definition, raw)),
+            PlaceholderType.Number => new NumberValue(ParseNumber(definition, raw)),
+            _ => throw new InvalidDataException(
+                $"Platzhalter „{definition.Name}“ vom Typ {definition.Type} kann keinen konstanten Textwert verwenden."),
+        };
+    }
+
+    private static DateOnly ParseDate(PlaceholderDefinition definition, string raw)
+    {
+        if (DateOnly.TryParse(raw, CultureInfo.InvariantCulture, DateTimeStyles.None, out var date)
+            || DateOnly.TryParse(raw, CultureInfo.GetCultureInfo("de-DE"), DateTimeStyles.None, out date)) return date;
+        throw Error(definition, "Datum, z. B. 2026-08-30");
+    }
+
+    private static decimal ParseNumber(PlaceholderDefinition definition, string raw)
+    {
+        if (decimal.TryParse(raw, NumberStyles.Number, CultureInfo.InvariantCulture, out var number)
+            || decimal.TryParse(raw, NumberStyles.Number, CultureInfo.GetCultureInfo("de-DE"), out number)) return number;
+        throw Error(definition, "Zahl");
+    }
+
+    private static InvalidDataException Error(PlaceholderDefinition definition, string expected) =>
+        new($"Konstanter Wert für „{definition.Name}“ ist ungültig; erwartet wird: {expected}.");
+}
diff --git a/LehrerApp.Templating/TemplateLoader.cs b/LehrerApp.Templating/TemplateLoader.cs
index 700a816..5069211 100644
--- a/LehrerApp.Templating/TemplateLoader.cs
+++ b/LehrerApp.Templating/TemplateLoader.cs
@@ -111,6 +111,8 @@ public sealed class TemplateLoader(TemplateLimits? limits = null,
                 issues.Add(new(ValidationSeverity.Error, $"Platzhalter „{used}“ wird im Layout verwendet, aber nicht im Manifest deklariert."));
             foreach (var duplicate in manifest.Placeholders.GroupBy(x => x.Name, StringComparer.Ordinal).Where(x => x.Count() > 1))
                 issues.Add(new(ValidationSeverity.Error, $"Platzhalter „{duplicate.Key}“ ist mehrfach deklariert."));
+            foreach (var issue in TemplateDataResolver.ValidateConstants(manifest))
+                issues.Add(new(ValidationSeverity.Error, issue));
             if (issues.Count > 0) throw new TemplateValidationException(new(issues));
             return new(manifest, layout, assets, sourceName);
         }
@@ -123,6 +125,7 @@ public sealed class TemplateLoader(TemplateLimits? limits = null,
         var issues = new List<ValidationIssue>();
         foreach (var placeholder in template.Manifest.Placeholders)
         {
+            if (placeholder.IsConstant) continue;
             if (!providedTypes.TryGetValue(placeholder.Name, out var actual))
             {
                 if (placeholder.Required) issues.Add(new(ValidationSeverity.Error, $"Pflichtwert „{placeholder.Name}“ fehlt."));
diff --git a/LehrerApp.Templating/TemplateRichText.cs b/LehrerApp.Templating/TemplateRichText.cs
new file mode 100644
index 0000000..cd9ad14
--- /dev/null
+++ b/LehrerApp.Templating/TemplateRichText.cs
@@ -0,0 +1,107 @@
+using System.Text;
+
+namespace LehrerApp.Templating;
+
+public sealed record TemplateRichTextRun(string Text, string? Placeholder, string? Format,
+    bool Bold, bool Italic, bool Underline)
+{
+    public bool IsPlaceholder => Placeholder is not null;
+}
+
+public static class TemplateRichText
+{
+    public static IReadOnlyList<TemplateRichTextRun> Parse(string source)
+    {
+        var runs = new List<TemplateRichTextRun>();
+        var literal = new StringBuilder();
+        var styles = new Stack<char>();
+
+        void Flush()
+        {
+            if (literal.Length == 0) return;
+            AddRun(runs, new(literal.ToString(), null, null,
+                styles.Contains('b'), styles.Contains('i'), styles.Contains('u')));
+            literal.Clear();
+        }
+
+        for (var index = 0; index < source.Length;)
+        {
+            if (source[index] == '\\' && index + 1 < source.Length
+                && source[index + 1] is '\\' or '[' or '$')
+            { literal.Append(source[index + 1]); index += 2; continue; }
+
+            if (TryTag(source, index, out var tag, out var closing, out var tagLength))
+            {
+                Flush();
+                if (closing)
+                {
+                    if (styles.Count == 0 || styles.Peek() != tag)
+                        throw new InvalidDataException($"Rich-Text-Tag [/{tag}] ist nicht passend geöffnet.");
+                    styles.Pop();
+                }
+                else styles.Push(tag);
+                index += tagLength; continue;
+            }
+
+            if (source[index] == '$' && TryPlaceholder(source, index, out var name, out var format, out var length))
+            {
+                Flush();
+                AddRun(runs, new("", name, format,
+                    styles.Contains('b'), styles.Contains('i'), styles.Contains('u')));
+                index += length; continue;
+            }
+
+            literal.Append(source[index++]);
+        }
+
+        Flush();
+        if (styles.Count > 0) throw new InvalidDataException($"Rich-Text-Tag [{styles.Peek()}] wurde nicht geschlossen.");
+        return runs;
+    }
+
+    public static IReadOnlyList<string> UsedPlaceholders(string source) => Parse(source)
+        .Where(x => x.Placeholder is not null).Select(x => x.Placeholder!).Distinct(StringComparer.Ordinal).ToList();
+
+    private static bool TryTag(string source, int index, out char tag, out bool closing, out int length)
+    {
+        tag = default; closing = false; length = 0;
+        if (index + 2 < source.Length && source[index] == '[' && source[index + 2] == ']'
+            && source[index + 1] is 'b' or 'i' or 'u')
+        { tag = source[index + 1]; length = 3; return true; }
+        if (index + 3 < source.Length && source[index] == '[' && source[index + 1] == '/'
+            && source[index + 3] == ']' && source[index + 2] is 'b' or 'i' or 'u')
+        { tag = source[index + 2]; closing = true; length = 4; return true; }
+        return false;
+    }
+
+    private static bool TryPlaceholder(string source, int index, out string name, out string? format, out int length)
+    {
+        name = ""; format = null; length = 0;
+        if (index + 1 >= source.Length) return false;
+        if (source[index + 1] == '{')
+        {
+            var end = source.IndexOf('}', index + 2);
+            if (end < 0) throw new InvalidDataException("Platzhalter mit '${' wurde nicht mit '}' geschlossen.");
+            var content = source[(index + 2)..end];
+            var parts = content.Split('|', 2);
+            name = parts[0].Trim(); format = parts.Length == 2 ? parts[1] : null;
+            if (name.Length == 0) throw new InvalidDataException("Ein eingebetteter Platzhaltername darf nicht leer sein.");
+            length = end - index + 1; return true;
+        }
+        if (!IsNameStart(source[index + 1])) return false;
+        var cursor = index + 2;
+        while (cursor < source.Length && IsNamePart(source[cursor])) cursor++;
+        name = source[(index + 1)..cursor]; length = cursor - index; return true;
+    }
+
+    private static bool IsNameStart(char value) => char.IsLetter(value) || value == '_';
+    private static bool IsNamePart(char value) => char.IsLetterOrDigit(value) || value is '_' or '.' or '-';
+
+    private static void AddRun(List<TemplateRichTextRun> runs, TemplateRichTextRun run)
+    {
+        if (!run.IsPlaceholder && runs.LastOrDefault() is { IsPlaceholder: false } previous
+            && previous.Bold == run.Bold && previous.Italic == run.Italic && previous.Underline == run.Underline)
+            runs[^1] = previous with { Text = previous.Text + run.Text };
+        else runs.Add(run);
+    }
+}