User blog comment:Master Sima Yi/Assassinews 05-08-'14 – Assassin's Creed: Rogue announced/@comment-95.176.186.15-20141003184430/@comment-3244113-20141003211348

I think they said back when they were marketing ACB, that they had a lot planned for Rome to be playable... but they just couldn't fit it into the game... so they fleshed it out and Brotherhood was born (AKA: the high ups saw the drawing board, and the annualising of the franchise was born)