strong to assault. The campaign ended without the British achieving their main objective of weakening France's naval power. The first British troops were withdrawn on 7 September, though a disease-ravaged garrison was maintained until 9 December. The failure of the campaign led to the resignation of the British prime minister, the Duke of Portland, and his replacement by Spencer Perceval. Austro-Polish War Austria invaded the Duchy of Warsaw with initial success. Poniatowski's army lost to the Austrians at the Battle of Raszyn on 19 April and Warsaw was occupied four days later, with the occupation lasting until 1 June. The Poles went on to invade Galicia, with some success, but the offensive quickly stalled with heavy casualties. The Austrians also won a few battles but were hampered by Russian troops whose intentions were unclear and did not allow them to advance. After the Austrian invasion of the Duchy of Warsaw, Russia reluctantly entered the war against Austria to fulfil their treaty of alliance with France. The Russian army, under the command of General Sergei Golitsyn, crossed into Galicia on 3 June 1809. Golitsyn advanced as slowly as possible, with instructions to avoid any major confrontation with the Austrians. There were minor skirmishes between the Russian and Austrian troops, with minimal losses. The Austrian and Russian commanders were in frequent correspondence and shared some operational intelligence. A courteous letter sent by a Russian divisional commander, General Andrey Gorchakov, to Archduke Ferdinand was intercepted by the Poles, who sent an original to Emperor Napoleon and a copy to Tsar Alexander, resulting in Gorchakov's removal from command by Alexander. There were constant disagreements between Golitsyn and Poniatowski, with whom the Russians were supposed to cooperate in Galicia. As a result of the Treaty of Schönbrunn, Russia received the Galician district of Tarnopol. The war at sea Since the Napoleonic Wars started, British fleets launched numerous attacks on French fleets, ports, or colonies and British and French navies continued their fighting in 1809. Britain overwhelmed France in the Atlantic after the French defeat at Trafalgar Campaign and Atlantic campaign of 1806, and remnants of French fleet was stationed at bases in Bay of Biscay. French colonies on the Caribbean and the Atlantic provided shelters and could be major threats to the British fleet. The French Atlantic Fleet was blockaded in Brest by a British force under James Gambier but the French were keen to