User blog comment:Master Sima Yi/AC: Brotherhood's E3 trailer released/@comment-2127564-20100615153239

The Armor of Altaïr in AC2 is black, which means it is worn by Grand Masters of The Order, it is optional. The Armor of Ezio in ACB is worn by Master Assassins, like Altaïr in AC1, which is completely white. Think of it that way