Al-Musta'in (Egypt)

Abu al-Fadl al-Abbas ibn Muhammad (c. 1390–February or March 1430), commonly known as al-Musta'in II, was the 10th "shadow" Abbasid caliph of Cairo, reigning under the tutelage of the Egyptian Mamluk sultans from 1406 to 1414. He was the only Cairo-based caliph to hold political power as Sultan of Egypt, albeit for only six months in 1412. All the other Cairene caliphs who preceded or succeeded him were spiritual heads lacking any temporal power.