Index: Doc/library/mailbox.rst
===================================================================
--- Doc/library/mailbox.rst	(revision 62996)
+++ Doc/library/mailbox.rst	(working copy)
@@ -277,20 +277,16 @@
 ^^^^^^^^^^^^^^^^
 
 
-.. class:: Maildir(dirname[, factory=rfc822.Message[, create=True]])
+.. class:: Maildir(dirname[, factory=None[, create=True]])
 
    A subclass of :class:`Mailbox` for mailboxes in Maildir format. Parameter
    *factory* is a callable object that accepts a file-like message representation
    (which behaves as if opened in binary mode) and returns a custom representation.
    If *factory* is ``None``, :class:`MaildirMessage` is used as the default message
    representation. If *create* is ``True``, the mailbox is created if it does not
-   exist.
+   exist. It is for historical reasons that *dirname* is named as such rather
+   than *path*.
 
-   It is for historical reasons that *factory* defaults to :class:`rfc822.Message`
-   and that *dirname* is named as such rather than *path*. For a :class:`Maildir`
-   instance that behaves like instances of other :class:`Mailbox` subclasses, set
-   *factory* to ``None``.
-
    Maildir is a directory-based mailbox format invented for the qmail mail
    transfer agent and now widely supported by other programs. Messages in a
    Maildir mailbox are stored in separate files within a common directory
Index: Lib/mailbox.py
===================================================================
--- Lib/mailbox.py	(revision 62996)
+++ Lib/mailbox.py	(working copy)
@@ -18,7 +18,6 @@
 import email
 import email.message
 import email.generator
-import rfc822
 import io
 try:
     if sys.platform == 'os2emx':
@@ -223,7 +222,7 @@
 
     colon = ':'
 
-    def __init__(self, dirname, factory=rfc822.Message, create=True):
+    def __init__(self, dirname, factory=None, create=True):
         """Initialize a Maildir instance."""
         Mailbox.__init__(self, dirname, factory, create)
         if not os.path.exists(self._path):
@@ -1932,7 +1931,7 @@
 
 class _Mailbox:
 
-    def __init__(self, fp, factory=rfc822.Message):
+    def __init__(self, fp, factory=email.message_from_file):
         self.fp = fp
         self.seekp = 0
         self.factory = factory
@@ -2049,7 +2048,7 @@
 
 class MHMailbox:
 
-    def __init__(self, dirname, factory=rfc822.Message):
+    def __init__(self, dirname, factory=email.message_from_file):
         import re
         pat = re.compile('^[1-9][0-9]*$')
         self.dirname = dirname
Index: Lib/test/test_mailbox.py
===================================================================
--- Lib/test/test_mailbox.py	(revision 62996)
+++ Lib/test/test_mailbox.py	(working copy)
@@ -526,7 +526,7 @@
         # Initialize a non-existent mailbox
         self.tearDown()
         self._box = mailbox.Maildir(self._path)
-        self._check_basics(factory=rfc822.Message)
+        self._check_basics(factory=None)
         self._delete_recursively(self._path)
         self._box = self._factory(self._path, factory=None)
         self._check_basics()
@@ -537,7 +537,7 @@
         for subdir in '', 'tmp', 'new', 'cur':
             os.mkdir(os.path.normpath(os.path.join(self._path, subdir)))
         self._box = mailbox.Maildir(self._path)
-        self._check_basics(factory=rfc822.Message)
+        self._check_basics(factory=None)
         self._box = mailbox.Maildir(self._path, factory=None)
         self._check_basics()