User blog comment:D. Cello/Assassinews 02/16 -- AC3 date released/@comment-86.181.124.14-20120218195302/@comment-1153722-20120220104430

It's called Assassin's Creed III because Assassin's Creed: Brotherhood isn't called Assassin's Creed III and Assassin's Creed: Revelations isn't called Assassin's Creed IV. Simple as that. :)

Why do people always ask this?