Yemen was stable during the Rashidun Caliphate. Yemeni tribes played a pivotal role in the Islamic expansion of Egypt, Iraq, Persia, the Levant, Anatolia, North Africa, Sicily, and Andalusia. Yemeni tribes who settled in Syria, contributed significantly to the solidification of Umayyad rule, especially during the reign of Marwan I. Powerful Yemenite tribes such as Kindah were on his side during the Battle of Marj Rahit.
Several emirates led by people of Yemeni descent were established in North Africa and Andalusia. Effective control over entire Yemen was not achieved by the Umayyad Caliphate. Imam Abdullah ibn Yahya Al-Kindi was elected in 745 CE to lead the Ibāḍī movement in Hadramawt and Oman. He expelled the Umayyad governor from Sana’a and captured Mecca and Medina in 746. Al-Kindi, known by his nickname “Talib al-Haqq” (seeker of truth), established the first Ibadi state in the history of Islam but was killed in Taif around 749.
Muhammad ibn Abdullah ibn Ziyad founded the Ziyadid dynasty in Tihama around 818 CE. The state stretched from Haly (in present-day Saudi Arabia) to Aden. They nominally recognized the Abbasid Caliphate but were ruling independently from their capital in Zabid. The history of this dynasty is obscure. They never exercised control over the highlands and Hadramawt, and did not control more than a coastal strip of Yemen (Tihama) bordering the Red Sea. A Himyarite clan called the Yufirids established their rule over the highlands from Saada to Taiz, while Hadramawt was an Ibadi stronghold and rejected all allegiance to the Abbasids in Baghdad. By virtue of its location, the Ziyadid dynasty of Zabid developed a special relationship with Abyssinia. The chief of the Dahlak islands exported slaves, as well as amber and leopard hides, to the then ruler of Yemen.
The first Zaidi imam, Yahya ibn al-Husayn, arrived in Yemen in 893 CE. He was the founder of the Zaidi imamate in 897. He was a religious cleric and judge who was invited to come to Saada from Medina to arbitrate tribal disputes. Imam Yahya persuaded local tribesmen to follow his teachings. The sect slowly spread across the highlands, as the tribes of Hashid and Bakil, later known as “the twin wings of the imamate,” accepted his authority.
Yahya established his influence in Saada and Najran. He also tried to capture Sana’a from the Yufirids in 901 CE but failed miserably. In 904, the Isma’ilis under Ibn Hawshab and Ali ibn al-Fadl al-Jayshani invaded Sana’a. The Yufirid emir As’ad ibn Ibrahim retreated to Al-Jawf, and between 904 and 913, Sana’a was conquered no less than 20 times by Isma’ilis and Yufirids. As’ad ibn Ibrahim regained Sana’a in 915. Yemen was in turmoil as Sana’a became a battlefield for the three dynasties, as well as independent tribes.
The Yufirid emir Abdullah ibn Qahtan attacked and burned Zabid in 989, severely weakening the Ziyadid dynasty. The Ziyadid monarchs lost effective power after 989, or even earlier than that. Meanwhile, a succession of slaves held power in Zabid and continued to govern in the name of their masters, eventually establishing their own dynasty around 1022 or 1050 according to different sources. Although they were recognized by the Abbasid Caliphate in Baghdad, they ruled no more than Zabid and four districts to its north. The rise of the Isma’ili Sulayhid dynasty in the Yemeni highlands reduced their history to a series of intrigues.