diff --git a/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj b/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj
index 7bc89fe..059f02a 100644
--- a/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj
+++ b/ClosedXML/ClosedXML/ClosedXML/ClosedXML.csproj
@@ -162,6 +162,8 @@
     <Compile Include="Excel\Ranges\Sort\XLSortElements.cs" />
     <Compile Include="Excel\Ranges\Sort\IXLSortElement.cs" />
     <Compile Include="Excel\Ranges\Sort\IXLSortElements.cs" />
+    <Compile Include="Excel\RichText\XLRichString.cs" />
+    <Compile Include="Excel\RichText\IXLRichString.cs" />
     <Compile Include="Excel\RichText\XLRichText.cs" />
     <Compile Include="Excel\RichText\IXLRichText.cs" />
     <Compile Include="Excel\Style\Colors\XLColor_Static.cs" />
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/IXLRichString.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/IXLRichString.cs
new file mode 100644
index 0000000..7425c22
--- /dev/null
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/IXLRichString.cs
@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace ClosedXML.Excel.RichText
+{
+    public interface IXLRichString
+    {
+        IXLRichText AddText(String text);
+        IXLRichString Clear();
+        IXLRichText Characters(Int32 index, Int32 length);
+    }
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichString.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichString.cs
new file mode 100644
index 0000000..dc4f987
--- /dev/null
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichString.cs
@@ -0,0 +1,54 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace ClosedXML.Excel.RichText
+{
+    internal class XLRichString: IXLRichString
+    {
+        List<IXLRichText> richTexts = new List<IXLRichText>();
+        public IXLRichText AddText(String text)
+        {
+            var richText = new XLRichText(text);
+            richTexts.Add(richText);
+            return richText;
+        }
+        public IXLRichString Clear()
+        {
+            richTexts.Clear();
+            return this;
+        }
+
+        public override string ToString()
+        {
+            var sb = new StringBuilder(richTexts.Count);
+            richTexts.ForEach(rt => sb.Append(rt.Text));
+            return sb.ToString();
+        }
+
+        public IXLRichText Characters(Int32 index, Int32 length)
+        {
+            List<IXLRichText> newRichTexts = new List<IXLRichText>();
+            Int32 runningLength = 0;
+            foreach (var rt in richTexts)
+            {
+                if (runningLength + rt.Text.Length > index + 1)
+                {
+                    Int32 startIndex = index - runningLength + 1;
+                    if (startIndex > 0)
+                    {
+                        var newRT = new XLRichText(rt.Text.Substring(0, startIndex + 1), rt);
+                        newRichTexts.Add(newRT);
+                    }
+                }
+                else
+                {
+                    newRichTexts.Add(rt);
+                    runningLength += rt.Text.Length;
+                }
+            }
+            richTexts = newRichTexts;
+        }
+    }
+}
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichText.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichText.cs
index 700ca98..8e93ec2 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichText.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/RichText/XLRichText.cs
@@ -9,6 +9,10 @@
     {
         public XLRichText(String text)
         {
+        }
+
+        public XLRichText(String text, IXLRichText defaultRichText)
+        {
             Text = text;
 
             var defaultFont = XLWorkbook.DefaultStyle.Font;