In 1808, Napoleon's rivalry with Britain led to an ill-fated intervention in Portugal and Spain, that sparked a nationalist revolt against the French. At Bailén Napoleon's Empire suffered its first major defeat, and though Napoleon himself then arrived in Spain to reassert French military dominance, he could not prevent the escape of Sir John Moore's small British army, after its defensive victory at Corunna on 16 January 1809. The British army would return, under new leadership, to play a major part in his downfall.