diff --git a/pyth/plugins/rtf15/reader.py b/pyth/plugins/rtf15/reader.py
index 7a74162..29f83e6 100644
--- a/pyth/plugins/rtf15/reader.py
+++ b/pyth/plugins/rtf15/reader.py
@@ -469,7 +469,10 @@ def handle_ansicpg(self, codepage):
         if codepage in _CODEPAGES_BY_NUMBER:
             self.charset = self.reader.charset = _CODEPAGES_BY_NUMBER[codepage]
         else:
-            raise ValueError("Unknown codepage %s" % codepage)
+            if self.reader.errors == 'ignore':
+                pass
+            else:
+                raise ValueError("Unknown codepage %s" % codepage)
 
 
     def handle_fonttbl(self):