Plague estates paid for Sultan Hasan's Cairo mosque, a minaret fell and killed about 300, and the sultan was murdered and never buried in his tomb

Al-Nasir Hasan became Mamluk sultan of Egypt at 13 in 1347 or 1348. The plague of 1348 killed many of Cairo's rich. Emirs arrested Hasan in 1351 and held him for about three years before he returned to power. In 1356 he began a mosque and madrasa below the Citadel. Al-Maqrizi, writing about six decades later, reported that it cost 30,000 dirhams a day and more than a million dinars in all. Part of the money came from plague estates: the property of wealthy Egyptians who died without heirs, and the wealth of Mamluk amirs who died in the plague, including Amir Shaykhu, which the state confiscated. Austerity under the emir Manjaq and extortion of subjects paid for the rest. In 1361 one of the planned minarets collapsed during building and killed about 300 people, including children at a school below. That year Hasan was assassinated by his army commander, Yalbugha al-Umari. His body was never found. The tomb chamber holds a cenotaph dated 1384 and the bodies of two of his young sons. Work went on until 1363. The endowment deed provided space for a doctor and medical students. In 1391 rebels fired on the Citadel from the roof, and Sultan Barquq had the entrance stairs destroyed. In 1517 the last Mamluk sultan sheltered there under Ottoman bombardment. The building is an active mosque within the UNESCO site of Historic Cairo.