Greek Brotherhood of Assassins

The Greek Assassins were a branch of Assassins located in Greece.

As of 1511, the Greek Assassins in Athens were having problems with retaining the trust of the people since the city came under Ottoman rule. Receiving aid from Ottoman Assassins, the Greek Assassins convinced the people that they were an independent organization, not working for any nation.

Source

 * Assassin's Creed: Revelations - Mediterranean Defense