33.1 Tribes Pay Alms Money Islam spread from Medina in all directions, to the north, to the south, and towards the east. Most of the tribes began to embrace this new religion that was far superior to anything they had known. It spread until it reached the borders of the Roman and the Persian empires, thus covering nearly the whole peninsula. The Arabs who had been disunited warring tribes began to be, for the first time, one united nation with a central authority in Medina and one religion whose sanctuary was in Mecca. The tribes who had entered into Islam paid willingly the alms tax that was an obligation on the believers. Those who had not entered into Islam paid a defense tax in exchange for security of person and property.