The Yemen had been the first province…
December 632 CE
The Yemen had been the first province to rebel against the authority of Islam, when the tribe of Ans rose in arms under the leadership of its chief and self-proclaimed prophet Al-Aswad, the Black One, who was killed by Fayruz the Persian, while the Prophet Muhammad still lived, and thereafter Fairoz had acted as governor of Yemen at San'a.
When word arrives that the Prophet Muhammad has died, the people of the Yemen again revolt, this time under the leadership of a man named Qais bin Abd Yaghus.
The avowed aim of the apostates is to drive the Muslims out of the Yemen, and they decide to achieve this objective by assassinating Fayruz and other important Muslim leaders, thus rendering the Muslim community leaderless.
Fayruz somehow manages to escape and take shelter in the mountains.
This happens in June or July 632.
For the past six months, Fayruz has remained in his mountainous stronghold, where over the months he is joined by thousands of Muslims of Yeman.
When Fayruz feels strong enough, he leads his men against Qais, and marches to San'a and defeats Qais, who retreats with his remaining men northeast to Abyan, where they all surrender and are subsequently pardoned by the Caliph.
The Muslim Arabs thus displace the Persians in southern Arabia and its antique native culture merges into the ascendant Islamic culture.