Background
Yusuf bin Yahya was a son of the imam al-Mansur Yahya who died in 976.
Yusuf bin Yahya was a son of the imam al-Mansur Yahya who died in 976.
In the following year, Yusuf was proclaimed with the regnal name ad-Da'i Yusuf. His early years were filled with struggles against the Yu'firid Dynasty that ruled much of the Yemeni highland. Ad-Da'i Yusuf managed to gain recognition as prince in San'a and the surrounding province in 978, reciting the khutbah in his own name.
Nevertheless, the Ziyadid governor Ibn ad-Dahhak soon fought back. After Abdallah's death in 997, Yu'firid rule collapsed. For ad-Da'i Yusuf, this was but a brief respite.
With the assistance of the Hamdan tribesmen, ad-Da'i Yusuf was expelled from Sa'dah, the traditional seat of the imams. After some years, al-Qasim bin al-Husayn changed his allegiance to ad-Da'i Yusuf again. Al-Mansur al-Qasim al-Iyyani retired from power in 1002, and ad-Da'i Yusuf ruled for a second term.
However, his time was filled with petty fighting over San'a, where the tribesmen of Hamdan and Khawlan played a major role. He also had to fight al-Mansur's son who posed as imam under the name al-Mahdi al-Husayn. This uneasy situation persisted until the death of ad-Da'i Yusuf in 1012, after an extremely turbulent reign.