area's defensive capabilities. He resided in a fort with mud walls and there were only a few huts in the vicinity. As a result of no centralized authority existing in Qatar from the 18th to 19th centuries, Rahmah was able to establish dominion over much of the peninsula for a period after the Al Khalifa relocated to Bahrain. Alliance with Saudis Rahmah's alliances with regional powers tended to be on the basis of shared opposition to the Al Khalifa: he formed an alliance with the first Saudi dynasty when it conquered Bahrain, and he founded and relocated to the fort of Dammam in 1809. Though some of his exploits were deemed piratical by the British, J. G. Lorimer, a British historian, remarks on Rahmah's scrupulously correct conduct and his compliance with the laws of warfare. He generally avoided encounters with British cruisers so that he would not incur their anger. In 1809, after the British expedition of the Pirate Coast, many Qasimi refugees fled to Khor Hassan. Rahmah, the leader of Khor Hassan, reached a compromise with the British in which he agreed not to harbour any fugitivites in return for the sparing of the town. The British also sent a warning to the Saudi amir to demand the prevention of Rahmah from launching any attacks on the British. He influenced the Saudis to launch an invasion of Bahrain in 1809. That greatly strengthened his position in Qatar, rendering him the most powerful tribal leader in the peninsula. Within a short duration, Rahmah had captured eighteen Utub vessels. However, in 1811, the combined forces of Said bin Sultan, Sultan of Muscat and Oman and the Al Khalifa successfully drove out the Wahhabi from Qatar and Bahrain. Rahmah then transferred his headquarters from Khor Hassan to his fort in Dammam. Alliance with Omanis In 1816, he allied himself with the rulers of Muscat in their failed invasion of Bahrain, and broke his alliance with the Saudis. The Saudis then destroyed the fort of Dammam in July 1816, and he took refuge in Bushehr, bringing around 500 families with him. Said bin Sultan proposed that he become a subject of Muscat and settle in Oman, but Rahmah refused. He moved back to Dammam in 1818. Subsequent campaigns He assisted the British forces in the Persian Gulf campaign of 1819 against the Al-Qasimi of Ras Al Khaimah. The operation was carried out after