Original sentence: Immigration to the Arabian Peninsula began in earnest in the 2nd century CE , and by the 6th and 7th centuries there was a considerable Jewish population in Hejaz , mostly in and around Medina , in part because of the embrace of Judaism by such leaders as Dhu Nuwas (who was very aggressive about converting his subjects to Judaism, and who persecuted Christians in his kingdom as a reaction to Christian persecution of Jews)  and Abu Karib Asad
Edited sentence: Immigration to the Arabian Peninsula began in earnest in the 2nd century CE, and by the 6th and 7th centuries there was a considerable Jewish population in Hejaz, mostly in and around Medina, in part because of the embrace of Judaism by such leaders as Dhu Nuwas (who was very aggressive about converting his subjects to Judaism, and who persecuted Christians in his kingdom as a reaction to Christian persecution of Jews) and Abu Karib Asad