The Persian Gulf campaign of 1819 was a British punitive expedition, principally against the Arab maritime force of the Al Qasimi in the Persian Gulf, which embarked from Bombay, India in November 1819 to attack Ras Al Khaimah. The campaign was militarily successful for the British and led to the signing of the General Maritime Treaty of 1820 between the British and the Sheikhs of what was then known as the "Pirate Coast", would become known as the "Trucial Coast" after this treaty. Today, the territory comprises much of the United Arab Emirates. Background After decades of incidents where British shipping had fallen foul of the aggressive Al Qasimi, an expeditionary force embarked for Ras Al Khaimah in 1809. This campaign led to the signing of a peace treaty between the British and Hussan Bin Rahmah, the Al Qasimi leader. This broke down in 1815. J. G. Lorimer contends that after the dissolution of the arrangement, the Al Qasimi "now indulged in a carnival of maritime lawlessness, to which even their own previous record presented no parallel". In 1815, the crew of a British Indian vessel were captured by Al Qasimi near Muscat and most of the crew were murdered. Then, on 6 January Al Qasimi captured an armed pattamar, the Deriah Dowlut, off the coast of Dwarka and murdered 17 of its 38 Indian crew. In the Red Sea, in 1816, three British-flagged Indian merchant vessels from Surat were taken and most of the crews killed. Following the incident involving the Surat vessels (said to have been carried out by Amir Ibrahim, a cousin to the Al Qasimi Ruler Hassan Bin Rahmah) an investigation took place and Ariel was despatched to Ras Al Khaimah from Bushire, to where it returned with a flat denial of involvement in the affair from the Al Qasimi who were also at pains to point out they had not undertaken to recognise 'idolatrous Hindus' as British subjects, let alone anyone from the West Coast of India other than Bombay and Mangalore. A small squadron assembled off Ras Al Khaimah and, on Sheikh Hassan continuing to be 'obstinate', opened fire on four vessels anchored there. Firing from too long a range, the squadron expended some 350 rounds to no effect; it then disbanded, visiting other ports on the coast. Unsurprisingly, given this ineffective 'punishment', Lorimer reports "The temerity of the pirates increased" and further raids