The eighteenth and nineteenth centuries were a turbulent time for Arabia in general and for the gulf in particular. To the southeast, the Al Said of Oman were extending their influence northward, and from Iraq the Ottoman Turks were extending their influence southward. From the east, both the Iranians and the British were becoming increasingly involved in Arab affairs.

The most significant development in the region, however, was the Wahhabi movement. The name Wahhabi derived from Muhammad ibn Abd al Wahhab, who died in 1792. He grew up in an oasis town in central Arabia where he studied Hanbali law, usually considered the strictest of Islamic legal schools, with his grandfather. While still a young man, he left home and continued his studies in Medina and then in Iraq and Iran.

When he returned from Iran to Arabia in the late 1730s, he attacked as idolatry many of the customs followed by tribes in the area who venerated rocks and trees. He extended his criticism to practices of the Twelver Shia, such as veneration of the tombs of holy men. He focused on the central Muslim principle that there is only one God and that this God does not share his divinity with anyone. From this principle, his students began to refer to themselves as muwahhidun (sing., muwahhid), or "unitarians." Their detractors referred to them as "Wahhabis."

Muhammad ibn Abd al Wahhab considered himself a reformer and looked for a political figure to give his ideas a wider audience. He found this person in Muhammad ibn Saud, the amir (see Glossary) of Ad Diriyah, a small town near Riyadh. In 1744 the two swore a traditional Muslim pledge in which they promised to work together to establish a new state (which later became present-day Saudi Arabia) based on Islamic principles. The limited but successful military campaigns of Muhammad ibn Saud caused Arabs from all over the peninsula to feel the impact of Wahhabi ideas.

The Wahhabis became known for a fanaticism similar to that of the early Kharijites. This fanaticism helped to intensify conflicts in the gulf. Whereas tribes from the interior had always raided settled communities along the coast, the Wahhabi faith provided them with a justification for continuing these incursions to spread true Islam. Accordingly, in the nineteenth century Wahhabi tribes, under the leadership of the Al Saud, moved at various times against Kuwait, Bahrain, and Oman. In Oman, the Wahhabi faith created internal dissension as well as an external menace because it proved popular with some of the Ibadi tribes in the Omani interior.

Wahhabi thought has had a special impact on the history of Qatar. Muhammad ibn Abd al Wahhab's ideas proved popular among many of the peninsula tribes, including the Al Thani clan, before the Al Khalifa attempted to take over the area from Bahrain at the beginning of the nineteenth century. As a result, Wahhabi beliefs motivated Al Thani efforts to resist the attempt of the Al Khalifa, who rejected Wahhabism, to gain control of the peninsula. In the early 1990s, Wahhabism distinguished Qatar religiously from its neighbors.

Wahhabi fervor was also significant in the history of the present-day UAE. The Qawasim tribes that had controlled the area since the eighteenth century adapted Wahhabi ideas and transferred the movement's religious enthusiasm to the piracy in which they had traditionally engaged. Whereas Wahhabi thought opposed all that was not orthodox in Islam, it particularly opposed non-Muslim elements such as the increasing European presence in the Persian Gulf.

Data as of January 1993