with a British victory at the battle of Lyngør in 1812, involving the destruction of the last large Dano–Norwegian ship—the frigate Najaden. Poland In 1807 Napoleon created a powerful outpost of his empire in Central Europe. Poland had recently been partitioned by its three large neighbours, but Napoleon created the Grand Duchy of Warsaw, which depended on France from the very beginning. The duchy consisted of lands seized by Austria and Prussia; its Grand Duke was Napoleon's ally the king of Saxony, but Napoleon appointed the intendants who ran the country. The population of 4.3 million was released from occupation and by 1814 sent about 200,000 men to Napoleon's armies. That included about 90,000 who marched with him to Moscow; few marched back. The Russians strongly opposed any move towards an independent Poland and one reason Napoleon invaded Russia in 1812 was to punish them. The Grand Duchy was absorbed into Russian Empire as a semi-autonomous Tsardom of Poland in 1815; Poland did not become a state again until 1918, following the dissolution of the Russian Empire. Napoleon's impact on Poland was huge, including the Napoleonic legal code, the abolition of serfdom, and the introduction of modern middle-class bureaucracies. Peninsular War, 1808–1814 The Iberian conflict began when Portugal continued trade with Britain despite French restrictions. When Spain failed to maintain the Continental System, the uneasy Spanish alliance with France ended in all but name. French troops gradually encroached on Spanish territory until they occupied Madrid, and installed a client monarchy. This provoked an explosion of popular rebellions across Spain. Heavy British involvement soon followed. After defeats in Spain suffered by France, Napoleon took charge and enjoyed success, retaking Madrid, defeating the Spanish and forcing a withdrawal of the heavily out-numbered British army from the Iberian Peninsula (Battle of Corunna, 16 January 1809). But when he left, the guerrilla war against his forces in the countryside continued to tie down great numbers of troops. The outbreak of the War of the Fifth Coalition prevented Napoleon from successfully wrapping up operations against British forces by necessitating his departure for Austria, and he never returned to the Peninsular theatre. The British then sent in a fresh army under Sir Arthur Wellesley (later the Duke of Wellington). For a time, the British and Portuguese remained restricted to the area around Lisbon (behind their impregnable lines of Torres Vedras), while their Spanish allies were besieged