About Obadiah ben Bulan, HaKohen al-Khazari
Obadiah(Khazar) (Heb. עבדיה) was the name of a Khazar ruler of the late eighth or early ninth century. He is described as coming from among "the sons of the sons" of Bulan, but whether this should be taken literally to mean that he was Bulan's grandson, or figuratively to imply a more remote descent, is unclear.
As a religious reformer, he encouraged the migration of Jews to Khazaria, built yeshivot, and promoted Rabbinic beliefs. He was succeeded by his son Hezekiah.