Capture of Gibraltar - Background

Background

At the start of the War of the Spanish Succession Portugal was nominally an ally of the Bourbons: France under Louis XIV, and Spain under his grandson, Philip V. Although she was not a belligerent Portugal's harbours were closed to the enemies of the Bourbon powers – principally the vessels of England and the Dutch Republic. However, following the Anglo-Dutch naval victory at Vigo Bay in 1702 the balance of naval forces had swung in favour of the Grand Alliance. Having now the ability to cut off Portugal's food supplies and trade (particularly gold from Brazil) it was not hard for the Allied diplomats to induce King Peter II to sign the Methuen Treaties of May 1703 and join the Alliance. Once Peter II had committed himself to war the Allied fleets gained access to Portugal's harbours, in particular the port of Lisbon. In return for his allegiance Peter II had demanded military and financial aid and territorial concessions in Spain; he had also asked that the Allies send to Lisbon Emperor Leopold I's younger son, Charles – the Allies' Habsburg candidate to the Spanish throne – to demonstrate the earnestness of their support. Known to his supporters as Charles III of Spain, the young pretender arrived in Lisbon – via London – with George Rooke's fleet on 7 March 1704, amid great celebrations.

Apart from the failed Allied attempt on Cádiz in 1702, and the subsequent attack on the Spanish treasure fleet in Vigo Bay, the war had thus far been limited to the Low Countries and Italy. With Portugal's change of allegiance, however, the war moved towards Spain. In May 1704 the court at Lisbon received news that French and Spanish troops had crossed the frontier into Portugal. This army of approximately 26,000 men under Philip V and the Duke of Berwick scored several victories on the border: Salvaterra fell on 8 May, Penha Garcia on 11 May, Philip V personally oversaw the fall of Castelo Branco on 23 May, and T'Serclaes captured Portalegre on 8 June. But without supply for their forces, the coming summer heat made it impossible for them to continue with the campaign, and Philip V returned to Madrid on 16 July to a heroes welcome. However, the heat did not affect the war at sea where the Allies were in a position of strength.