diff --git a/slack/channels.py b/slack/channels.py
index ef5401f..d6f4e87 100644
--- a/slack/channels.py
+++ b/slack/channels.py
@@ -11,14 +11,12 @@ from . import users
 class Channel(threads.Thread):
     def __init__(self, json):
         threads.Thread.__init__(self, json)
-        self.__member  = json.get("is_member", False)
+        self.api_history = "channels.history"
+        self.__member    = json.get("is_member", False)
 
     def do_fetch_info(self):
         return info(self.id())
 
-    def do_fetch_messages(self, ts):
-        return history(self.id(), ts)
-
     def do_mark_messages(self, ts):
         mark(self.id(), ts)
 
@@ -27,12 +25,6 @@ class Channel(threads.Thread):
 
 
 
-def history(channel, timestamp):
-    ret = api.call("channels.history", token = auth.token(), channel = channel, oldest = timestamp)
-    if ret["ok"] == False:
-        return None
-    return ret["messages"]
-
 def info(channel):
     ret = api.call("channels.info", token = auth.token(), channel = channel)
     if ret["ok"] == False:
diff --git a/slack/groups.py b/slack/groups.py
index 663d521..94d6fd9 100644
--- a/slack/groups.py
+++ b/slack/groups.py
@@ -9,25 +9,16 @@ from . import threads
 class Group(threads.Thread):
     def __init__(self, json):
         threads.Thread.__init__(self, json)
+        self.api_history = "groups.history"
 
     def do_fetch_info(self):
         return info(self.id())
 
-    def do_fetch_messages(self, ts):
-        return history(self.id(), ts)
-
     def do_mark_messages(self, ts):
         mark(self.id(), ts)
 
 
 
-def history(group, timestamp):
-    ret = api.call("groups.history", token = auth.token(), channel = group, oldest = timestamp)
-    if ret["ok"] == False:
-        return None
-    return ret["messages"]
-
-
 def info(group):
     ret = api.call("groups.info", token = auth.token(), channel = group)
     if ret["ok"] == False:
diff --git a/slack/im.py b/slack/im.py
index d3458ab..055fc4c 100644
--- a/slack/im.py
+++ b/slack/im.py
@@ -9,8 +9,9 @@ from . import users
 class IM(threads.Thread):
     def __init__(self, json):
         threads.Thread.__init__(self, json)
-        self.__uid  = json.get("user")
-        self.__user = users.info(self.__uid)
+        self.api_history = "im.history"
+        self.__uid       = json.get("user")
+        self.__user      = users.info(self.__uid)
 
     def name(self):
         return "Chat With %s" % self.__user.name()
@@ -21,20 +22,11 @@ class IM(threads.Thread):
     def do_fetch_info(self):
         return info(self.id(), self.__uid)
 
-    def do_fetch_messages(self, ts):
-        return history(self.id(), ts)
-
     def do_mark_messages(self, ts):
         mark(self.id(), ts)
 
 
 
-def history(im, timestamp):
-    ret = api.call("im.history", token = auth.token(), channel = im, oldest = timestamp)
-    if ret["ok"] == False:
-        return None
-    return ret["messages"]
-
 def info(im, uid):
     ret = api.call("im.open", token = auth.token(), user = uid, return_im = True)
     if ret["ok"] == False:
diff --git a/slack/threads.py b/slack/threads.py
index 250b5c1..d9c607f 100644
--- a/slack/threads.py
+++ b/slack/threads.py
@@ -1,15 +1,16 @@
 #
 # Copyright 2015 (c) Anna Schumaker.
 #
-
+from . import api
+from . import auth
 from . import chat
 
 #
 # This class represents a slack "thread", which could be a channel, group,
-# or chat.  Note that child classes need to implement the following methods:
+# or chat.  Note that child classes need to define the following variables:
 #
 # - do_fetch_info():     Call <whatever>.info to find unread count and timestamp.
-# - do_fetch_messages(): Call <whatever>.history to find unread messages.
+# - self.api_history:    The slack api method to find unread messages
 # - do_mark_messages():  Call <whatever>.mark to set unread cursor.
 #
 class Thread:
@@ -34,6 +35,13 @@ class Thread:
             self.__last_ts = json.get("last_read", None)
             self.__id      = json.get("id", 0)
 
+    def fetch_messages(self):
+        json = api.call(self.api_history, token = auth.token(),
+                        channel = self.__id, oldest = self.__last_ts)
+        if json["ok"] == False:
+            return None
+        return json["messages"]
+
     def id(self):
         return self.__id
 
@@ -51,7 +59,7 @@ class Thread:
             self.fetch_info()
 
         # Read original message list
-        messages = self.do_fetch_messages(self.__last_ts)
+        messages = self.fetch_messages()
         o_list = [ chat.Message(msg) for msg in messages ]
         o_list.sort()
         if len(o_list) == 0: