Yahya bin Hamza was a member of the Zaidi elite, but not of the dynasty of the Rassids that usually provided imams.
[1] The old Yemeni imam al-Mahdi Muhammad bin al-Mutahhar had conquered large highland territories from the Rasulid Dynasty, including the commercially and politically important city San'a.
With the city as his base, he waged war in the following years against Taiyabi Ismaili groups of the Hamdan tribe in the Wadi Dahr.
The imam was a prominent scholar who authored Al-Intisar, the most comprehensive Zaydiyyah law book, and Ad-Da'wa al-amma, a work encouraging struggle for the true faith.
[2] It was popularly said that the number of pages he wrote were equal to the days he lived.