Ruling families of the area known today as Yemen.
The Zaydi imamate in Yemen has its origins in 897, when al-Hadi ila al-Haqq Yahya became the first Zaydi imam (with his seat in Saʿda). His fame as an intellectual as well as a leader led to the invitation to Yemen; there he developed a multitude of policies that eventually became the basic guidelines for the religious as well as political characteristics of Yemeni Zaydism.
Yahya, however, was not able to consolidate his rule in all of Yemen; there were revolts as well as segments of the population that did not accept his pretensions to religio-political rule. Although he did not succeed in establishing any permanent administrative infrastructure, Yahya's descendants became the local aristocracy, and it is from among them that the imams of Yemen were selected for the next one thousand years.
Yemen throughout most of that period was only rarely a unified political entity; in fact, what was included within its frontiers varied widely, and it has not been governed consistently or uniformly by any single set of rulers. It existed as a part of a number of different political systems/ruling dynasties between the ninth and sixteenth centuries, after which it became a part of the Ottoman Empire.
After Imam Yahya's death, a multitude of smaller dynasties and families established themselves in the Tihama (the low coastal plain) as well as in the highlands. Among the better known of these are the Sulayhids, the Hatims, the Zuray'ids, and the Yu'firids. It was during this period, when the Fatimid state was influential, that a portion of the population was converted to Ismaʿili Shiʿism.
Beginning with the conquest of Yemen by the family of Salah al-Din ibn Ayyub (Saladin) in 1174, a series of dynasties exercised a modicum of control and administration in Yemen for roughly the next 400 years; these are, in chronological sequence, the Ayyubids, from 1173/74 to 1228; the Rasulids, from 1228 to 1454; the Tahirids, from 1454 to 1517; and the Mamluks, from 1517 to 1538, when the Ottoman Empire took the Yemeni Tihama.
During most of this period, the dynasties and their rulers were primarily engaged in familial, regional, and occasionally sectarian disputes. Ironically, the Sunni Rasulids, who eventually concentrated their rule in southern Yemen for precisely that reason, were the dynasty under which the region experienced the greatest economic growth and political stability.
Very little is known about the Zaydi imams and their efforts to establish themselves and develop some form of administration (including tax collection), or their success in promoting Zaydi goals during this period. From the available evidence, there was very little continuity and a great deal of competition among the Zaydi families and clans. For example, in a presumably representative two-hundred-year period from the thirteenth to the fifteenth centuries, there appear to have been more than twenty different candidates for the imamate, representing more than ten distinct clans.
Eventually, as the Europeans entered the Middle East, specifically the Portuguese and then others in the effort to control the Red Sea trade, Yemen and its Zaydi imams were increasingly unable to maintain their independence. It was not until the ascendancy of Imam Qasim ibn Muhammad and his son al-Mu'ayyad Muhammad in the early seventeenth century that the Zaydi Yemenis were able to resist the Ottoman Empire's forces and become an independent political entity.
see also ismaʿili shiʿism; zaydism.
manfred w. wenner