Abu Bakr allowed Usamah ibn Zayd’s army to depart at the end of Rabiʿ al-Awwal. The slaying of al-Aswad occurred in that same month, after Usamah had already set out; it was therefore the very first victory that Abu Bakr achieved while he was in Madinah.

The account of al-Aswad’s uprising, his seizure of power, and his death

We have already mentioned that Yemen belonged to the Himyarites and that their kings were known as the Tubbaʿs; in our discussion of pre-Islamic times we touched on this at some length.

Later, the king of Abyssinia sent two of his generals—Abraha al-Ashram and Aryat—who wrested Yemen from the Himyarites, so that the country came under Abyssinian rule. The two generals then quarreled; Aryat was killed and Abraha retained sole authority. Abraha built a church which he called al-Qullays (1)—so named for its great height—and sought to divert the Arabs’ pilgrimage to it instead of to the Kaʿbah. A group of Quraysh defiled the church, and when Abraha learned of this he swore that he would demolish the Sacred House in Mecca. He marched toward it with his troops and the elephant named Mahmūd, and what befell them is what Allah has related in His Book.

We have already given the full story in its proper place. Abraha returned with the small remnant of his army in the worst state imaginable, suffering a bitter defeat; his limbs continued to fall off, joint by joint, until, upon reaching Ṣanʿāʾ, his chest split open and he died. The kingship then passed to his son Yaksum (2) ibn Abraha, and after him to Yaksum’s brother Masrūq ibn Abraha. It is said that Abyssinian control of Yemen lasted seventy years.

Then Sayf ibn Dhī Yazan the Himyarite rose in revolt. He first went to Caesar, the Byzantine emperor, seeking help against them, but Caesar refused on account of the Christian faith they shared. Sayf therefore traveled to Khosrow, the king of Persia, and pleaded with him—in exchanges that we have partly detailed earlier. They finally agreed that Khosrow would send a contingent of prisoners, led by a man named Wahriz. With this force Sayf liberated Yemen from the Abyssinians, defeated and killed Masrūq ibn Abraha, entered Ṣanʿāʾ, and installed Sayf ibn Dhī Yazan on the throne, restoring the rule of his forefathers. Delegations came from every direction to congratulate him, yet Khosrow harbored ambitions concerning the land (3). Matters remained thus until the Messenger of Allah ﷺ was sent forth. He stayed in Mecca as long as he did, then emigrated to Madinah. When he dispatched letters to distant regions, inviting them to worship Allah alone with no partner, he also wrote to Khosrow, the king of Persia:

“In the name of Allah, the Most Gracious, the Most Merciful. From Muhammad, the Messenger of Allah, to Khosrow, the great one of Persia. Peace be upon whoever follows the guidance. To proceed: Submit and you will be safe…,” and so on.