The Acre harbor was the main port of Acre, located in the Middle District of the city, and was a location of strategic importance to the Crusader cause and Richard I of England during the Third Crusade.
The harbor covered a huge area and possessed two lighthouses located to the east and the south of the docks. It was separated from the rest of the city by huge walls, only accessible through two gates known as Saint John's Gate.
In 1191, Sibrand, Grand Master of the Knights Teutonic and secretly a Templar, planned a blockade of the harbor in order to prevent King Richard from receiving aid from overseas. However, the Levantine Assassin Altaïr Ibn-La'Ahad infiltrated the harbor and assassinated Sibrand on his own ship.