In an interview with Kotaku, Yves Guillemot revealed that the company is planning so far ahead in order to avoid franchise fatigue.
"We are making sure the teams who are creating the different iterations have enough timeâ€”two years, three years, so that they can take risk and they can change the concept enough so that it can be appealing and fresh," he said.
While he didn't go into specifics, it's a pretty safe assumption that one of the games is this year's Assassin's Creed IV: Black Flag. With regards to the other two, one is surely next year's Assassin's Creed game as that would need to be comfortably into development in order to meet its release deadline, but what of the other? Unless it's a spinoff for mobile or handheld devices, it's probably 2015's Assassin's Creed game, seeing as the franchise is now annualised.