So I was trying to get 100% sync in some old missions that I played, so when I reached that mission when Machiavelli shows you around Rome and asks you to buy that weak armor and weapon. So after buying them and beating the mission with 100% sync I lost the armor and (I think) the sword I forgot.
But I'm sure I lost the Armor of Brutus and it really me off, I tried to go to different memories and still the same problem, it's not even on the inventory or the armors list!
Go to the mission where you unlocked it and play the mission again. (If it is like in AC2, haven't played Brotherhood)
EDIT: Sorry for quote.
[Edited by ArchDuke, 7/16/2011 10:59:27 AM]