diff --git a/pyreadline/lineeditor/history.py b/pyreadline/lineeditor/history.py
index b4a0e84..0d42087 100644
--- a/pyreadline/lineeditor/history.py
+++ b/pyreadline/lineeditor/history.py
@@ -99,12 +99,16 @@ class LineHistory(object):
 
     def add_history(self, line):
         u'''Append a line to the history buffer, as if it was the last line typed.'''
+        if not isinstance(line, lineobj.TextLine):
+            line = lineobj.TextLine(line)
+
         if not line.get_line_text():
             pass
         elif len(self.history) > 0 and self.history[-1].get_line_text() == line.get_line_text():
             pass
         else:
             self.history.append(line)
+        
         self.history_cursor = len(self.history)
 
     def previous_history(self, current): # (C-p)