Soult followed up his success by storming the city,[3] in the course of which thousands of fleeing citizens drowned in the Porto Boat Bridge disaster.

After the Battle of Corunna, Napoleon ordered Marshal Nicolas Soult to invade Portugal from the north.

Napoleon failed to take into account both the wretched condition and the roads or the fact that a full-scale guerrilla war had broken out in Northern Portugal and Spain.

Soult's II Corps had four infantry divisions, commanded by Generals of Division Pierre Hugues Victoire Merle, Julien Augustin Joseph Mermet, Étienne Heudelet de Bierre, and Henri François Delaborde.

The French then moved northeast to Ourense in Spain, seized an unguarded bridge and marched south.

On the way, Franceschi's cavalry overran Major General Nicolás Mahy's Spanish brigade at La Trepa on 6 March, inflicting 700 casualties.

From Chaves, Soult moved west to Póvoa de Lanhoso where he was confronted by Baron Eben's 25,000-man army composed mostly of Portuguese militia armed with muskets, pikes, and agricultural implements.

Residents fled over the he bridge away from Porto towards the south, Gaia side, pursued by French troops.