diff --git a/src/knowledge_base.h b/src/knowledge_base.h
index 20ce65f..b1763b5 100644
--- a/src/knowledge_base.h
+++ b/src/knowledge_base.h
@@ -44,7 +44,7 @@ namespace obelisk
 
         public:
             KnowledgeBaseException() :
-                errorMessage_("an unknown error occured")
+                errorMessage_("an unknown error ocurred")
             {
             }