In India the outbreak of war with France encouraged the Marathas, who dominated the country from Mysore to the Ganges, in the hope of expelling the British, by acting in conjunction with Haidar Ali. Hastings found that a French agent was intriguing with them, and took prompt measures against them. An expedition from Bombay failed miserably, but Colonel Goddard, who was sent by Hastings from Bengal, captured Ahmadabad, and drove Sindhia over the Narbada. His fortress, Gwalior, was stormed by Major Popham in August, 1780. Nevertheless, the war strained Hastings's resources. His difficulties were terribly increased by the invasion of the Karnatic. Haidar and his son, Tipu, practically took the English by surprise, overran the country with an army of some 75,000 cavalry and 15,000 infantry, instructed by 400 Frenchmen; defeated the Madras troops, captured Arcot, and threatened Madras. Sir Eyre Coote, who had come out to conduct the Maratha war, was despatched to Madras, and in 1781 negotiations were opened with Sindhia, and his former possessions were restored to him. Peace was made with the Maratha confederacy in May, 1782, by the treaty of Salbai, which was ratified seven months later. While Coote was forcing Haidar to raise the siege of various British fortresses in January, 1781, a French fleet appeared at Pondicherry. Haidar called upon it to help him, for his own fleet had been destroyed by Admiral Hughes; but Coote prevented the French from obtaining supplies, and they sailed away without effecting anything. He gained a splendid victory over Haidar at Porto Novo on July 1, met him with doubtful success at Pollilur, completely routed him at Sholinghar, and, in January, 1782, though suffering from serious illness, skilfully relieved Vellore.