During the Fourth Fitna, Ibrahim was proclaimed caliph on 20 July 817 by the people of Baghdad, who gave him the regnal name of al-Mubarak () and declared his reigning nephew al-Ma'mun deposed. Ibrahim received the allegiance of the Hashemites. He had to resign in 819, and spent the rest of his life as a poet and a musician. He is remembered as "one of the most gifted musicians of his day, with a phenomenal vocal range", and a promoter of the then innovative 'Persian style' of song, 'which was characterized "inter alia" by redundant improvisation'.