In Assassin's Creed Revelations, which earlier Assassin's memories does Ezio investigate?

In Assassin's Creed Revelations, Ezio investigates the memories of Altaïr Ibn-La'Ahad.

The game brings together the two major protagonists of the first part of the series. Ezio travels to Constantinople in the early sixteenth century while pursuing keys connected to Altaïr's legacy and the hidden library at Masyaf. The memories reveal important events from Altaïr's later life.

Altaïr first appeared as the protagonist of the original Assassin's Creed, set during the Third Crusade. By the time of Revelations, he is portrayed at several later ages, allowing the game to show his leadership and the consequences of his decisions.

Desmond Miles also has a modern-day storyline in Revelations, so the game contains three connected timelines: Ezio's, Altaïr's, and Desmond's. This structure is why the title serves as a direct bridge between Ezio's trilogy and the series' larger mythology.