I have heard about Shaykh Abu Hasan Shadhili, that he fought the crusaders at al-Mansurah, even though he was old and almost blind. It was the 5th Crusade when the French King tried to invade Egypt from the sea, while the main Muslim army was in Palestine. Therefore the emergency Muslim army in al-Mansurah had large numbers of ordinary citizen volunteers including ulama, even old ones such as Shaykh Shadhili. It is said the du'a Hizbul-Nasr was composed by him at this time, and he fought with two swords.