This paper will address the relations between the two main polities in Yemen during the 13th-15th centuries: the Rasulid Sultans and the Zaydi Imams. After the last local Ayyubid sultan al-Malik al-Mas‘ud Yusuf left Yemen, an emir named Nur al-Din ‘Umar was left in charge, assuming a new dynasty known as the Rasulids in 626/1229. Calling himself al-Malik al-Mansur, the emir established his own power with the blessing of the caliph al-Mustansir, who accepted the new regime with a charge to battle the Zaydi imams entrenched in Yemen’s north. During the more than two centuries of Rasulid control in Yemen there were constant battles between the Shi‘a Zaydis and the Rasulids, who became predominantly Shafi‘i, but patronized all the Sunni schools. The bulk of Yemen’s population at the time was tribal, with shifting alliances and constant rebellions against the authority of both polities. Based in the southern highland capital of Ta‘izz and the coastal city of Zabid, the first three Rasulid sultans were largely successful in gaining a foothold in the northern highland homeland of the Zaydi imams and became rivals with the last Egyptian Ayyubids and early Ba?r? Mamluks for control of Mecca. The Rasulids were never able to gain complete control of Yemen’s diverse geographical zones; there are records of peace agreements with the imams and local tribal leaders. The primary Rasulid historical chronicles and biographical texts, such as the works of Ibn Hatim, al-Janadi and al-Khazraji reflect a Rasulid bias, so it is important to examine relevant Zaydi sources to have a more balanced view of the conflict between them. The Zaydi sources include biographies of the relevant imams of the period.