diff --git a/beetsplug/parentwork.py b/beetsplug/parentwork.py
index 4520edea2..e03a142d4 100644
--- a/beetsplug/parentwork.py
+++ b/beetsplug/parentwork.py
@@ -26,7 +26,8 @@ import musicbrainzngs
 
 
 def work_father_id(mb_workid, work_date=None):
-    """ Given a mb_workid, find the id one of the works the work is part of"""
+    """ Given a mb_workid, find the id one of the works the work is part of
+    and the first composition date it encounters. """
     work_info = musicbrainzngs.get_work_by_id(mb_workid,
                                               includes=["work-rels",
                                                         "artist-rels"])
@@ -46,7 +47,7 @@ def work_father_id(mb_workid, work_date=None):
 
 
 def work_parent_id(mb_workid):
-    """Find the parentwork id of a work given its id. """
+    """Find the parentwork id and composition date of a work given its id. """
     work_date = None
     while True:
         new_mb_workid, work_date = work_father_id(mb_workid, work_date)
@@ -57,8 +58,8 @@ def work_parent_id(mb_workid):
 
 
 def find_parentwork_info(mb_workid):
-    """Return the work relationships (dict) of a parentwork given the id of
-    the work"""
+    """Return the work relationships (dict) and composition date of a
+    parentwork given the id of the work"""
     parent_id, work_date = work_parent_id(mb_workid)
     work_info = musicbrainzngs.get_work_by_id(parent_id,
                                               includes=["artist-rels"])
diff --git a/test/test_parentwork.py b/test/test_parentwork.py
index 44545c63e..985723fb5 100644
--- a/test/test_parentwork.py
+++ b/test/test_parentwork.py
@@ -80,9 +80,9 @@ class ParentWorkTest(unittest.TestCase, TestHelper):
     def test_father_work(self, command_output):
         mb_workid = u'2e4a3668-458d-3b2a-8be2-0b08e0d8243a'
         self.assertEqual(u'f04b42df-7251-4d86-a5ee-67cfa49580d1',
-                         parentwork.work_father(mb_workid)[0])
+                         parentwork.work_father_id(mb_workid)[0])
         self.assertEqual(u'45afb3b2-18ac-4187-bc72-beb1b1c194ba',
-                         parentwork.work_parent(mb_workid)[0])
+                         parentwork.work_parent_id(mb_workid)[0])
 
 
 def suite():