Internal disorders and changing trade routes have caused the Himyar kingdom to suffer political and economic decline.

In 516, Himyarite ruler Yusuf As'ar Yath'ar, who is known in Arabic tradition mostly by the nickname Dhu Nuwas, had proclaimed himself a Jew, possibly as a rampart against the encroaching Christian faith.

Some sources state that he was the successor of Rabī'ah ibn Mudhar, a member of the same dynasty; the archeologist Alessandro de Maigret believes he was a usurper.

Nashwad bin Sa'īd al-Ḥimyarī stated that he killed his predecessor with a stiletto hidden in his sandal while his predecessor was seducing the handsome Yūsuf in his chambers.

According to a number of medieval historians, who depend on the account of John of Ephesus, Dhū Nuwās, announced that he would persecute the Christians living in his kingdom because Christian states persecuted his fellow co-religionists in their realms; a letter survives written by Simon, the bishop of Beth Arsham in 524, recounting Dhū Nuwās' (where he is called Dimnon) persecution in Najran (modern al-Ukhdūd in Saudi Arabia).

The persecution is apparently described and condemned in the Qur'an (al-Buruj:4).