diff --git a/browser/common.py b/browser/common.py
index 1e400cb..ef4ef49 100644
--- a/browser/common.py
+++ b/browser/common.py
@@ -269,7 +269,10 @@ class BaseView(GenericView, I18NView):
             for c in cr:
                 try:
                     principal = pau.getPrincipal(c)
-                    creators.append(principal.title)
+                    if principal is None:
+                        creators.append(c)
+                    else:
+                        creators.append(principal.title)
                 except PrincipalLookupError:
                     creators.append(c)
         return creators