For those of you who have not yet played Assasin's Creed 2, or Assassin's Creed Brotherhood, Subject 16 left behind some puzzles called glyphs. Solving all the puzzles gives you a nice little achievement or trophie. Further on they unlock a video called the Truth. Here are those videos. For the real truth on the two clans, visit this link.

 http://assassinscreedfans.yolasite.com/the-real-truth.php

Assassin's Creed 2

Assassin's Creed Brotherhood