Battle of al-Qādisiyyah
While there were cases such as the Sassanid army division at Hamra, that converted "en masse" before pivotal battles such as the Battle of al-Qādisiyyah, conversion was fastest in the urban areas where Arab forces were garrisoned slowly leading to Zoroastrianism becoming associated with rural areas. Still at the end of the Umayyad period, the Muslim community was only a minority in the region.