Reference: "Divrei ha-Yamim le-Bnei Yahya,( דברי הימים לבני יחייא )", by Eliakim Carmoly, Printed in Frankfort am Main/Rodelheim, Published by: Isak Kaufman, 1850. Genealogy of, and biographical work on, the Yahya family by Eliakim Carmoly. There is an introduction from Carmoly, in which he informs that the Yahya family is one of distinction from the time of Maimonides. Originally achieving greatness in Portugal and Spain, they after settled in Italy and Turkey. The text is preceded by a chart of the family, beginning with the Nasi, Don Yahya, and concluding with Don Gedalia. The text, in seven chapters, is set in a single column, primarily in rabbinic type although there are instances of vocalized square letters, and is accompanied by extensive footnotes. The final page is an announcement of the forthcoming publication of seven minor Yerushalmi tractates by Carmoli. The text of this book was compared to the "bin Yahya Family Tapestry", currently stored in the antiquity archives of Jewish Theological Seminary in New York City, by Abraham Greenstein - grandson of Abraham Gindi HaKohen. The text matches the Tapestry.

Don Yahya passed away in the year 4982 and was called from the "ibn Ya'ish" family. He emigrated from Cordoba to Lisbon and was a scholar and King's Physician...and a gratly wealthy man.

2nd Chief Rabbi (Rabi Maior) of Portugal. Before that he was advisor to Alfonso 1 Conquerer, 1st King of Portugal (b1110), reigned from 1139-1185

He was the son of Yaish Ibn Yahya, resident of Lisbon, Portugal; scholar, politician, royal advisor, vast land holdings; advisor to Alfonso I (1st King of Portugal). By appointing Yahya Ibn Yaish (a/k/a Yahia Ben Rabbi ), as state treasurer, Alfonso paved the way for his successors to employ Jews in financial and administrative positions.

Ibn Yaish was not only "chief rabbi," but also the "chief cavalier." The king's heirs expanded the employment of Jews as administrators in the kingdom. So it was that during the reign of Portugal's first five kings, the situation of the Jews was good and they lived in security. The problems began later, but even during the period surrounding the 1391 pogrom against the Jews of Spain, Portugal served as a haven for the Jews of Castile.

Yahya Ibn Yaish, by his one (1) wife, had five sons:

1. Yaish Ibn Yahya, the father of three sons, namely, Yosef Jucef, Shlomo fl. 1255, and Moshe died 1279, had issue
2. Yakov Ibn Yahya, the father of Hiyya, the father of Eli
3. Yosef Ibn Yahya died 1264, the father of Shlomo Ha-Zaken who died 1299, the father of three sons, who were: Yosef Jucef, Gedaliah the father of David. Don Yosef ibn Yahya HaRav and Paloma, mistress of Fadrique Alfonso of Castile and Hiyya [Don Fadrique Alfonso of Castile, 1st Señor de Haro (1334 – 1358), 25th Master of the Knights of the Order of Santiago (1342-1358), was the fifth illegitimate child of Alfonso XI of Castile and Eleanor of Guzman]
4. Yehuda "Sar" Ibn Yahya, father of Yahya father of Yakov, father of Hiyya and Yosef
5. Yahya ibn Yahya, father of Shlomo father of Yosef and Abu Baqr Ibn Yahya (a convert to Islam)

During the tenure of Yahya HaNasi Maimonides assumed the role of Nagid, Vizier and physician to Saladin. The Egyptian rabbinate, the leader of which held the title of Nagid, and who were, in the main, descendants of Maimonides, ruled the Land of Israel as well as Egypt proper and any other territory under Egyptian rule. The only exception was Maimonides himself, who did not hold this title but performed many of its functions. Maimonides helped Saladin conquer Jerusalem – taking it back from the Christian invaders. Soon after Saladin's conquest, Jews were invited to return to Jerusalem and it was decided by the rabbis in Egypt that a "vice-Nagid" would be appointed to oversee internal Palestinian affairs. The first two who held this title was Hillel ben Moshe and Ovadiah ben Ulah.

Historical note - the ibn Yahya family were patrons of Maimonides. -------------------- http://www.davidicdynasty.org/chapter25.php