Missing part of ezio story?

[Isac542]

Hi! I'm sorry if I've posted this topic on the wrong place. In the beggining of assassins creed brotherhood when desmond first enters the sancuary under the villa auditore he see a gosth of ezio and he says " Wow he's so old, he must have returned way after the attack". Have i missed something because i havent found out why he returned and i've played both acb and ac revelations

[alientraveller]

"Where are you going?"
"To plant a seed."

I think Pixar or some similar group of filmmakers said the audience should be left to add two and two.

[LightRey]

He returned to leave behind the clues for the password to the vault at the end of ACB.