Hassan-i Sabbāh (c. 1050–1124) was a Persian leader of the Assassins in the Middle East from 1090 until his death. Under his leadership, the Brotherhood, notably its Levantine branch, transformed from a clandestine group into a public organization. He was also responsible for the reformation of the Hidden Ones into the Assassin Brotherhood.
Under his leadership, the Assassins established a sovereign state in their own right from their capital of Alamut in Persia. The move was unprecedented, marking the first time in history that the Brotherhood entered public consciousness. It was Hassan's hope that the public presence of the Assassins would make people realize that they were not alone in their fight against oppression and to inspire them to stand up for themselves—though the Assassins' practices continued to be kept closely guarded secrets.