David "Ya'ish" ibn Hiyya

According to Pinsker (sec. 1, p. 5), this Da'ud ibn Yaḥyā is one and the same as our decendant of Yehuda, as reasonably deduced from the facts that Yaḥyā is the usual Arabic praenomen equivalent of Judah, whereas ibn Zakarīyā’ represents a not infrequently attested scribal confusion of bin/ibn for Abū, the latter (i.e., Abū Zakarīyā’) being in fact the usual kunya for Judah (see Judah b. Joseph of Qayrawān).

Pinsker, Simcha. Liqquṭe Qadmoniyot (Zur Geschichte des Karaismus und der karäischen Literatur), Vienna, 1860.

David ibn Yahya was Administrator/Landlord of Templar lands in Monzon that were given to the Templars by Ramon Berengeur III (Count of Barcelona). David ben Hiyya HaNasi married the daughter of Rabbi Baruch ben Yitzhak Ibn Albalia – a very wealthy old family in Spain who had been there since the 2nd Temple period.. The Templars asked a number Jews to help them manage their estates. While in Monzon, David ben Hiyya teaches Jewish mysticism to the Knights Templar organization in order to learn about how Templar financial operations operates; David then teaches to his only known son, Yahya, how to manage Templar Banking on behalf of the Knights in Palestine.

David travels back to Palestine where he dies while fighting Mohammedans in an attempt to retake the Temple mount.. In the course of fighting he befriends Berenguer Ramon II and Knights Templar. David's son Yahya (Hiyya) returns to al-Andalus and strong ties to the Templars.

Two of David's piyutim (poems) were included in the compilation Betulat bat Yehudah by Samuel David Luzzatto who mistook the author for Ḥiyya ha-Ma'arabi, the collector of Judah ha-Levi's poems. David has at least one son, 1) Hiyya ben david HaNasi According to Lemay in “Dans L'Espagne” pg 650-52, and his “De La Scolastique” Sisnando Davidiz is the great-uncle of Abraham Ibn Daud and Hiyya ben David HaNasi; this therefore implies that Sinando Davidiz was the son of Hiyya ben David ben Zakai HaNasi; Sisnando's Hebrew name was Sheshnan Ibn Dauod who was kidnapped from his family and raised in the Caliph's court.