He was granted the rulership of a pocket principality in Anjuvannam, near Cranganore, and rights to seventy-two "free houses". These rights were engraved on a set of bronze tablets known as the "Sâsanam" (Burnell, "Indian Antiquary," iii. 333-334), which are still in the possession of the Jewish community of India. The date of the charter can be fixed at about 750; it can not, for paleographical reasons, have been much earlier than this, nor later than 774, since a grant made to the Nestorian Assyrians at that time was copied from it.
Joseph's descendants continued to exercise dominion over the Jews of the Malabar coast until a conflict broke out between one of his descendants, Joseph Azar, and his brother in the 1340s. The ensuing strife led to intervention by neighboring potentates and the eradication of Jewish autonomy in southern India.