In 1641, after the outbreak of the Portuguese Restoration War, the Portuguese government, with Dutch and French help, prepared to start the offensive against Spain at sea. Dom António Telles da Silva, who had fought the Dutch in India, was designated commander of squadron of 16 ships, which along of another 30 of the Dutch Republic under Artus Gijsels, was entrusted the mission of capture and hold the Spanish towns of Cádiz and Sanlúcar. The attempts failed thanks to the fortuitous encounter that they had with 5 Dunkirkers under Judocus Peeters, who was chasing a flotilla of Algerian privateers, off Cape St. Vincent. Peeters managed to reach Cádiz without losing a single vessel and put on alert the Marquis of Ayamonte and Don Gaspar Alfonso Pérez de Guzmán, 9th Duke of Medina Sidonia.