A Khazar ruler during the early 10th century CE, Aaron ben Benjamin was the son of the Khazar king Benjamin. Whether Aaron, like the rest of the Bulanids, was a Khagan or a Bek is an unresolved issue.
According to the anonymous author of the Schechter Letter, during Aaron's reign a war was launched against Khazaria by a Byzantine-inspired coalition led by the Alans, who had been allies of Aaron's father Benjamin. [1] Aaron defeated his enemies with the help of Oghuz mercenaries and captured the king of the Alans. [1] Rather than execute his captive, he demanded an oath of fealty and spared his life. The Alan king's daughter married Aaron's son Joseph. [1] In Khazarian Hebrew Documents of the Tenth Century, Omeljan Pritsak dated this war to the early reign of Romanos I (i.e., the early 920s CE). [2]