Dirham - al-Mahdi citing Musa as heir

Al-Mahdi's designation of his son Musa al-Hadi as heir apparent was a calculated move to bypass his more capable — and ultimately more consequential — younger son Harun. Musa reigned for only fourteen months before his death in 786, widely suspected to have been engineered by his own mother al-Khayzuran to clear the way for Harun al-Rashid. Dirhams citing Musa in the heir's position thus document a succession arrangement that collapsed almost immediately, struck across a window of roughly two years before the political calculus changed permanently.