The Rasulid Dynasty was established in 1229 by Umar ibn Rasul, who was appointed deputy governor by the Ayyubids in 1223. When the last Ayyubid ruler left Yemen in 1229, Umar stayed in the country as caretaker. He subsequently declared himself an independent king by assuming the title “al-Malik Al-Mansur” (the king assisted by Allah). Umar established the Rasulid dynasty on a firm foundation and expanded its territory to include the area from Dhofar to Mecca.
Umar first established himself at Zabid, then moved into the mountainous interior, taking the important highland centre Sana’a. However, the Rasulid capitals were Zabid and Taiz. He was assassinated by his nephew in 1249. Omar’s son Yousef defeated the faction led by his father’s assassins and crushed several counter-attacks by the Zaydi imams who still held on in the northern highland. Mainly because of the victories he scored over his rivals, he assumed the honorific title “al-Muzaffar” (the victorious).