the crusaders to attack the Moors in Alcácer do Sal. The city of Alcácer had been lost since 1191 in the aftermath of the Third Crusade campaigns of Alvor and Silves. The keep in Alcácer was conquered for the first time by the Portuguese in 1160. In 1191, it returned to Amazigh hands under the direction of Yaqub al-Mansur, who transformed it into the military garrison of Garb al-Andalus. According to De itinere Frisonum the Frisian Crusaders refused to help on account of Innocent III prohibition to Bishop Souiro, and departed for the Holy Land, even after being provided food, expenses, and rousing oratories about the Almohads' annual demands for 100 Christians in tribute. Meanwhile, ships under the command of William I of Holland and Count George of Wied arrived in Alcácer do Sal on 2 August 1217. They were joined by the Portuguese sent to lay siege to the castle. Muslim governors in Seville, Córdoba, Jaén and Badajoz attempted to relieve the garrison but their reinforcements were defeated on 11 September. The castle surrendered on 18 October 1217, with additional Christian troops provided by Pedro Alvítiz from Castile. Once the castle was taken, many of the northern Crusaders requested Pope Honorius III allow them to remain for a year "for the liberation of Hispania" and "the extirpation of the perfidious cult of the pagans". The victory in Alcácer do Sal also motivated Alfonso IX of León, Sancho VII of Navarre, in addition to Iberian prelates and nobles, to break their truces with the Muslim leaders, in hopes that the northern Crusaders would continue their campaigns the following summer. But, the Pope granted only absolution from their vows to those who could not continue to the Holy Land, and the Crusaders left the Castle to the Portuguese and continued on to Acre. The capture of Al Qaşr was the only permanent conquest of the Fifth Crusade. In 1218, Alcacer do Sal received its foral from King Afonso II, and handed over to the Knights of Santiago, who made it their headquarters during their advance into the Alentejo and Algarve. The Order of Santiago dominated an area from Sesimbra until the Algarve, controlling the lower Sado, Alentejo Litoral and coast of Cape St. Vincent. At the end of the 13th century, the Order advanced to Mértola to support reconquest of the Algarve, but later retreated to Alcácer and remained there until