First built by Ptolemy I Soter and finished under Ptolemy II, it was dedicated to the Muses, the nine goddesses of the arts and daughters of Zeus, and was said to hold anywhere between 40,000 to 400,000 scrolls. It was part of a larger research institution known as the Mouseion of Alexandria. 
In 48 BCE, Bayek, having followed the clues in Aya's home travelled to the library in search of his beloved. There, he was greeted by Aya's cousin, Phanos the Younger, who explained the reason for Aya's absence. Phanos later directed the Medjay to the entrance to Aya's hideout beneath the library.
In 1511, during an excavation of the destroyed Library of Alexandria, the Mamluk Sultanate's soldiers discovered two Memory Seals in a chest from 331 BC. Ezio Auditore sent some Assassins from Constantinople to Alexandria to retrieve the Seals.
- Historically, the library was partially destroyed during the Siege of Alexandria. However in the events of the game, the library remained in one piece with no signs of damage whatsoever after the events of the siege.