Bahrain (Arabic: البحرين al-Baḥrayn) is a historical region in eastern Arabia that was known as the Province of Bahrain (Arabic: إقليم البحرين, Iqlīm al-Baḥrayn) until the 16th Century. It stretched from the south of Basra along the Persian Gulf coast and included the regions of Kuwait, Al-Hasa, Qatif, Qatar, and the Awal Islands, now known as Bahrain. The name "Bahrain" referred to the eastern mainland Arabia until the 16th century at least. The Arab inhabitants of the province were called Bahranis after that time.
Until Bahrain embraced Islam in 629 AD, it was a center for Nestorian Christianity. The major tribe among its inhabitants was the Abdul Qais. In the early 7th Century, Bahrain became one of the first places in Arabia to become an Islamic state, despite its great distance from Muhammad's location in Medina.
In the year 899, the Qarmatians, a millenarian Ismaili sect, seized hold of the country and sought to create a utopian society based on reason and the distribution of all property evenly among the initiates. The Qarmatians caused widespread disruption throughout the Islamic world and sacked Mecca and Medina in 930, carrying off the sacred Black Stone to Qatif where it was held for ransom. They were defeated in 976 by the Abbasids.
The people of eastern Arabia are still sometimes called Bahranis and their language is Bahrani Arabic. The Bahranis were traditionally settled (non-nomadic). They inhabited oases and coastal areas.