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.
EXILARCH, in Jewish history, "Chief or Prince of the Captivity."
Hence the head of the Babylonian Jews was the exilarch (in Aramaic Resh Galutha) .
Some traditions regarded the last king of Davidic descent (Jehoiachin) as the first exilarch, and all the later holders of the dignity claimed to be scions of the royal house of Judah.
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.