Yaghmurâsan b. Zayyân emerged from a minor Zenata Berber branch while serving as an Almohad governor at Tlemcen. In 1235, as Almohad authority disintegrated, he broke away and founded his own dynasty. The new kingdom faced stronger neighbours to the west and east as well as Arab nomadic pressure from the south, making its survival dependent on political flexibility and military skill.

Yaghmurâsan recognized the economic importance of the commercial routes passing through Tlemcen. After an unsuccessful attempt in 1257, he conquered Sijilmasa in 1264 and held it for almost a decade. This temporarily placed Tlemcen and Sijilmasa, described as the two most important outlets of trans-Saharan trade, under a single authority.

The Zayyanids soon lost Sijilmasa to the Marinids, and Tlemcen itself became the object of repeated Marinid sieges. Nevertheless, Yaghmurâsan’s foundation endured for over three centuries, demonstrating the resilience of a kingdom positioned between competing Maghribi powers. The dynasty’s later history retained the strategic and commercial priorities established during his rule.