Benjamin of Tudela (Itinerary, p. 61) names an exilarch Daniel b.
Hence the head of the Babylonian Jews was the exilarch (in Aramaic Resh Galutha) .
In the 6th century an attempt was made to secure by force political autonomy for the Jews, but the exilarch who led the movement (Mar Zutra) was executed.
The exilarch could excommunicate, and no doubt had considerable jurisdiction over the Jews.
The exilarch then delivered a discourse, and in the benediction or doxology (Qaddish) his name was inserted.
The Babylonian Jews were practically independent, and the exilarch (reshgalutha) or prince of the captivity was an official who ruled the community as a vassal of the Persian throne.
A spirited description of the glories of the exilarch is given in D'Israeli's novel Alroy.
Our chief knowledge of the position and function of the exilarch concerns the period beginning with the Arabic rule in Persia.
In the age succeeding the Mahommedan conquest the exilarch was noted for the stately retinue that accompanied him, the luxurious banquets given at his abode, and the courtly etiquette that prevailed there.
The last exilarch of importance was David, son of Zakkai, whose contest with Seadiah had momentous consequences.