After his long pursuit of a British army across northwest Spain, Soult was defeated at the Battle of Corunna on 16 January 1809. After the Royal Navy evacuated the British army, Napoleon ordered Soult to invade northern Portugal and the marshal began his march south on 4 March. In the Battle of Braga on 20 March, the French routed a large but poorly armed body of Portuguese militia, inflicting severe losses. On 29 March, Soult's corps attacked the Portuguese defenders in the First Battle of Porto and the slaughter was even worse. The French easily broke through the Portuguese defenses and 7,000–8,000 Portuguese were killed or drowned in the massacre and stampede that followed.