In 1261, Balian of Arsuf leased the Arsuf fort to Knights Hospitallers for 4,000 bezants a year in the hopes that the Knights would fortify the city against the threat posed by Baibars.

After being given command of the city, the knights started building a fort there in 1263, most likely in an effort to increase the size of the eastern portion of the walls.

[3] On March 21/22, 1265, a large and well-equipped Mamluk army led by the sultan himself besieged the fort of Arsuf.

Baibars laid siege to the city for 35 days, and on April 26, the Mamluk launched a fierce assault that successfully pushed the Hospitallers to the citadel.

The rest of the knights fought off the Mamluks for the next three days until they surrendered on condition they would depart freely.