They are know as the ten Batlaaneem (men of leisurely devotion to the community), for they occupy themselves with nothing other than the needs of the community... Over all of them is Daniel b. Chasday, who is called the "Exilarch of All Israel." ...The Jews address him as Our Lord the Exilarch and the Muslims address him as Sayyidnaa Ibn Daa'ud. He has been invested with supreme authority over the congregation of Israel by the Ameer al-Mu'mineen, the lord of the Muslims. For thus Muhammad commanded concerning the Exilarch and his descendants, and he issued him a seal of authority over all the sacred congregations living under his rule. Likewise, he ordered that every individual, be he Muslim or Jew, or member of any other people within his kingdom, should rise up before him and salute him, and that whoever does not rise up before him should receive one hundred lashes.
Every Thursday, when he goes to behold the face of the great Caliph, he is accompanied by Gentile and Jewish horsemen, and heralds cry out before him: "Make way for our Lord, the scion of David, as is due him!" In their language they say: "I'maloo tareeq li-Sayyidnaa Ibn Daa'ood." He rides on horseback wearing garments of embroidered silk with a large turban on his head. Over the turban is a large white shawl upon which is a chain. And on it is the seal of Muhammad. When he comes before the Caliph, he kisses his hand. Then the Caliph rises before him, seats him upon a throne which Muhammad had ordered to be made in his honor. And all of the Muslim princes who have come to behold the face of the Caliph rise altogether before him. The Exilarch then sits upon his throne facing the Caliph, for thus did Muhammad command in order to fulfill the scriptural verse:
The scepter shall not pass from Judah,
Nor the rule's staff from between his feet;
Until he come to Shiloh,
and the homage of peoples be him. (Gen. 49.10)
Benjamin of Tudela's Description of Baghadadi Jewry (Second Half of the Twelfth Century), cited in Norman Stillman's The Jews of Arab Lands, (JPS, 1979) pp. 253