He belonged to the Qasimid family which descended from the Islamic prophet Muhammad, and dominated the Zaidi imamate in 1597–1962.
When his cousin and predecessor al-Mahdi Ahmad died in 1681, a number of Qasimids laid claim to the imamate.
Through the diplomatic efforts of the Ulema (religious scholars) the dispute was settled without bloodshed, and al-Mu'ayyad Muhammad II gained power.
[1] Al-Mu'ayyad Muhammad II was not a warlike leader, but rather an ascetic and deeply religious personality who was devoted to learning.
[2] Seven contenders claimed the succession after him in a period of only three years; of these, al-Mahdi Muhammad finally gained power in 1689 after a violent struggle.