Editing Altaïr Ibn-La'Ahad (section)

===Later Life and Death===
In the decade following his return to the Order, Altaïr began constructing a library beneath the Masyaf fortress, where he stored thousands of books filled with the knowledge he had acquired from the Apple. The five Memory Seals he recorded during his time in Alamut served as keys for accessing this library. Once the library was completed, Altaïr invited the Venetian explorers Niccolò and Maffeo Polo to Masyaf. Altaïr shared stories of his life with Niccolò, which would later be passed on to Niccolò's son, Marco, in the form of a journal.

Altaïr also began spreading the Order beyond Masyaf, aiming to establish Assassin Guilds in new countries. He believed the Polos could play a key role in this expansion. With Darim’s help, he removed his books from the Masyaf library, giving some to the Polos and sending the rest to Alexandria.

In August 1257, Masyaf was besieged by the Mongols, forcing Niccolò and Maffeo to leave. Before their departure, Altaïr entrusted them with his Codex, relying on them to spread the teachings of the Assassin Order. He escorted them out of Masyaf, using the Apple of Eden to fend off the Mongols. At the gates, Altaïr gave Niccolò five of the six Memory Seals he had recorded, asking him to keep them hidden to prevent them from falling into the wrong hands.

After the Polos left, Altaïr returned to Masyaf’s castle. Once he confirmed that the fortress had been fully evacuated, he met with Darim outside the library. Although initially puzzled by his father's actions, Darim soon realized that the library was intended as a vault. Altaïr confirmed this and revealed his plan to seal both the Apple and himself inside.

After bidding farewell to his son and urging him to return to their family and live well, Altaïr entered the library and locked it. He concealed the Apple behind a far wall and seated himself in a chair at the center of the library. Altaïr imprinted the memory of his farewell to Darim and the moments leading up to that point onto his sixth and final seal. Once he completed this, Altaïr Ibn-La'Ahad laid his hand over the seal on his knee, tilted his head to one side, and peacefully passed away at the age of 92.