During the 18th century, the Maratha Empire expanded rapidly, claiming Konkan and much of eastern Gujarat from the disintegrating Mughal Empire. In western Gujarat, including Kathiawar and Kutch, the loosening of Mughal control allowed numerous local rulers to create virtually independent states. In 1737, Salsette was captured by Baji Rao I of the Maratha Empire from the Portuguese, and the Portuguese province of Bassein was ceded to the Marathas in 1739. The growth of the Bengal provinces soon undermined Bombay's supremacy. In 1753, Bombay was made subordinate to Calcutta. Thereafter, Bengal always maintained much greater importance relative to Madras and Bombay. Bankot (Fort Victoria) in Konkan was incorporated into Bombay Presidency in 1756. The First Anglo-Maratha War began with the Treaty of Surat, which was signed on 6 March 1775, between Raghunathrao of the Maratha Empire and the British. According to the treaty, Raghunathrao ceded Salsette and Bassein to the British. The war ended when Salsette, Elephanta, Hog Island, and Karanja were formally ceded to the British by the Treaty of Salbai, signed on 17 May 1782. These territories were incorporated into the Bombay Presidency. Also according to the treaty, Bassein and its dependencies were restored to Raghunathrao, while Bharuch was ceded to the Maratha ruler Scindia. The British annexed Surat on 15 May 1800. The British received the districts of Ahmadabad, Bharuch and Kaira in 1803 after British victory in the Second Anglo-Maratha War.