إقليم البحرين
With Eastern Arabia more firmly under Sasanian control, and with the establishment of Sasanian garrison troops, the way for Zoroastrianism was opened. Pre-Islamic Arabian poets often makes mention of Zoroastrianism practices, which they must have either made contact with in Asoristan or Eastern Arabia. In c. 531/2, shah Khosrow I () appointed the Lakhmid king al-Mundhir III ibn al-Nu'man as the ruler of Mazun.