Source: US State Department
In the 7th century, Islamic caliphs began to exert control over the area. After this caliphate broke up, the former north Yemen came under control of Imams of various dynasties usually of the Zaidi sect, who established a theocratic political structure that survived until modern times. (Imam is a religious term. The Shi’ites apply it to the prophet Muhammad's son-in-law Ali, his sons Hassan and Hussein, and subsequent lineal descendants, whom they consider to have been divinely ordained unclassified successors of the prophet.)
Egyptian Sunni caliphs occupied much of north Yemen throughout the 11th century. By the 16th century and again in the 19th century, north Yemen was part of the Ottoman Empire, and in some periods its Imams exerted control over south Yemen.
NOTE: The information regarding Yemen on this page is re-published from the US State Department. No claims are made regarding the accuracy of Yemen History information contained here. All suggestions for corrections of any errors about Yemen History should be addressed to the State Department.