diff --git a/umbra/words.py b/umbra/words.py
index 98841c643622d25926eaa556dacab001e3a3d16f..f2dc49ee80c514b3a3bbb0dec94a4d04a9b934f0 100644
--- a/umbra/words.py
+++ b/umbra/words.py
@@ -249,7 +249,7 @@ class Sentence(list):
                 if self[index].has_source():
                     return index
                 index -= 1
-        return -1
+        return index
     
     def __str__(self):
         return ' '.join([word.word for word in self])