Peninsular War 1808: Roliça, Vimeiro, Tudela, Napoleon in Spain and the second siege of Zaragoza

Background. The war had started when French and Spanish armies invaded and occupied Portugal in 1807, transiting through Spain, but it escalated in 1808 after Napoleonic France occupied Spain, which had been its ally. In 1808 the Spanish army in Andalusia defeated the French at Bailén, considered the first open-field defeat of a Napoleonic army on a European battlefield. Napoleon had installed his brother Joseph as King of Spain, provoking the Peninsular War.

Portuguese Campaign. In August 1808, British troops landed in Portugal under Lieutenant-General Arthur Wellesley. Wellesley's forces defeated General Henri François Delaborde's outnumbered division at Roliça on 17 August. Subsequently, on 21 August, Wellesley defeated Major-General Jean-Andoche Junot's main force at Vimeiro near Lisbon, marking the first British battles of the Peninsular War.

Spanish Campaign. In November 1808, French Marshal Jean Lannes attacked a Spanish army under General Castaños at Tudela. After defeating a Spanish army at Somosierra on 30 November, Napoleon's vanguard arrived in Madrid on 1 December, with the city capitulating on 4 December. The second siege of Zaragoza did not commence until 20 December 1808, following the city's successful resistance during the first siege from 15 June to 14 August 1808.