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. Aaron defeated his enemies with the help of Oghuz mercenaries and captured the king of the Alans.