In Assassin's Creed II, what is the name of the secret organization that trains Ezio after his family is executed?

In Assassin's Creed II, the secret organization that trains Ezio after his family is executed is the Assassin Brotherhood.

Ezio Auditore's training begins after a conspiracy leads to the public execution of his father and brothers in Florence. He escapes with his mother and sister and later reaches Monteriggioni, where his uncle Mario reveals the family's Assassin heritage. Mario then introduces Ezio to the Brotherhood's methods, symbols, equipment, and long-running conflict with the Templars.

The Assassin Brotherhood is the series' historical organization dedicated to protecting free will and opposing attempts to impose total control. Its members work covertly and often rely on intelligence, allies, and infiltration rather than open armies. In Assassin's Creed II, Ezio's path gradually changes from personal revenge into a broader commitment to the Brotherhood's cause.

The Hidden Ones are the earlier organization founded by Bayek and Aya in Assassin's Creed Origins, while the Medjay is Bayek's title and profession. The Templar Order is the Brotherhood's principal ideological opponent, not the group that trains Ezio. Those distinctions matter because the games portray related organizations across different historical periods.