Lost Legacy was a virtual representation of one of Ezio Auditore da Firenze's genetic memories, relived by Desmond Miles in 2012 through the Animus, in which a memory from Altaïr Ibn-La'Ahad was viewed.
Altaïr Ibn-La'Ahad and his son, Darim took the final preparations for the moving of the Assassin Order to a new location. Altaïr, however, decided to remain in Masyaf, advising his son to live a peaceful life.
- Altaïr: You have seen to my books?
- Darim: Yes. Some we sent with the Polos. The rest will go with me to Alexandria.
- Altaïr: Good. Very good.
- Darim: Father, I do not understand... Why did you build a library if you did not intend to keep your books—
- Altaïr: You should go. When the Mongols return, Masyaf must be empty.
- Darim: I see. This is not a library at all. It is a vault.
- Altaïr: It must stay hidden, Darim. Far from eager hands. At least until it has passed on the secret it contains.
- Darim: What secret?
- Altaïr: Go, son. Go be with your family, and live well.
- Darim: All that is good in me, began with you, father.
Darim departed and Altaïr entered his vault. While preparing everything in the vault, Altaïr heard voices from his past.
- Al Mualim: In much wisdom, is much grief. And he that increaseth knowledge, increaseth sorrow.
- Maria: What does it tell you? What do you see?
- Altaïr: Strange visions and messages. Of ones who came before, of their rise, and their fall...
- Maria: But what happens to us, Altaïr? To our family! What does the Apple say?
- Altaïr: Who were the ones who came before? What brought them here? How long ago?
- Maria: Get rid of that thing!
- Altaïr: This is my duty, Maria! Maria? Where... where are you? Where is she!
- Darim: Gone, father. You do not remember? She's gone!
- Altaïr: If you are asked, say I sent the Apple away. Tell them I sent it to Cyprus, or Cipango, or that I dropped it into the sea. Tell them anything to keep men away from this place. This Apple must not be found, not until the time is right.
Altaïr locked the Apple away and took his seat.
Altaïr stored the Apple in the vault and sat down to rest afterwards, accepting death's embrace.
- The name of the memory shares the name of the cancelled Nintendo 3DS game Assassin's Creed: Lost Legacy. The basic premise of the cancelled game was ultimately merged with that of Revelations.
- While Altaïr talks with his son Darim, his robes may appear to be black in the reflection of a puddle nearby.
- Altaïr's line "Who were the ones who came before? What brought them here? How long ago?" is taken from a passage in his Codex, which can be read in Assassin's Creed II.
- This memory is the first and only time we see Altaïr without his hood.