supplies forced them to retreat in September and the attack was not repeated. As agreed at Compiègne in 1635, the French replaced Swedish garrisons in Alsace; prior to his death in 1639, Bernard of Saxe-Weimar won a series of victories over the Imperials in the Rhineland, notably the capture of Breisach in December 1638. Severing the Spanish Road meant their armies in Flanders had to be resupplied by sea, making them vulnerable to attack by the Dutch navy, which destroyed a large Spanish fleet at the Battle of the Downs in 1639. Although most convoys managed to get through, it illustrated the difficulties Spain faced in sustaining its war effort in the Low Countries. With Spanish resources stretched to the limit in Europe, the Dutch used the opportunity to attack their possessions in the Americas, Africa and Asia, especially those belonging to the Portuguese Empire, then also ruled by Philip IV; Spanish inability to protect these interests caused increasing unrest in Portugal. Damage to the economy and tax increases imposed to pay for the war led to protests throughout Spanish territories, which in 1640 erupted into open revolts in Portugal and Catalonia. In 1641, the Catalan Courts recognised Louis XIII of France as Count of Barcelona, and ruler of the Principality of Catalonia. However, they soon found the new administration differed little from the old, turning the war into a three sided contest between the Franco-Catalan elite, the rural peasantry, and the Spanish. Louis XIII died on 14 May 1643, and was succeeded by his five-year-old son, Louis XIV, whose mother, Anne of Austria, took control of the Regency Council that ruled in his name. Five days later, Condé, then known as the duc d'Enghien, defeated the Spanish Army of Flanders at Rocroi; while less decisive than often thought, the loss of this highly experienced unit ended Spanish dominance of the European battlefield. It gave Condé, a member of the royal family, and effective ruler of large parts of eastern France, leverage in his struggle with Anne, and Cardinal Mazarin. Despite some successes in northern France and the Spanish Netherlands, including victory at Lens in August 1648, France was unable to knock Spain out of the war. In the Holy Roman Empire, Imperial victories at Tuttlingen and Mergentheim were offset by French success at Nördlingen and Zusmarshausen. In Italy, French-backed Savoyard offensives against the Spanish-ruled Duchy of Milan achieved little,