Crossbow

Ezio overlooking the Colosseum with a crossbow on his back.

The crossbow is a long awaited weapon for the Assassin's Creed series. This weapon was originally seen in the trailer for Assassin's Creed, however it was not included in the game.

There is also hinted to be a crossbow in the upcoming Assassin's Creed: Brotherhood as one is seen on the back of an Assassin on a screenshot.