This meant Britain was the only power inclined to help Victor Amadeus achieve this objective and he changed sides in 1703 after the Royal Navy won control of the Western Mediterranean. Military campaigns; 1701–1708 Italy The war in Italy primarily involved the Spanish-ruled Duchies of Milan and Mantua, considered essential to the security of Austria's southern borders. In 1701, French troops occupied both cities and Victor Amadeus II, Duke of Savoy, allied with France, his daughter Maria Luisa marrying Philip V. In May 1701, an Imperial army under Prince Eugene of Savoy moved into Northern Italy; by February 1702, victories at Carpi, Chiari and Cremona forced the French behind the Adda river. Vendôme, one of the best French generals, took command and was substantially reinforced; Prince Eugene managed a draw at the Battle of Luzzara but the French recovered most of the territory lost the year before. In October 1703, Victor Amadeus declared war on France; by May 1706, the French held most of Savoy except Turin while victories at Cassano and Calcinato forced the Imperialists into the Trentino valley. However, in July 1706 Vendôme and any available forces were sent to reinforce France's northern frontier after the defeat at Ramillies. Reinforced by German auxiliaries led by Leopold of Anhalt-Dessau, Prince Eugene broke the Siege of Turin in September; despite a minor French victory at Castiglione, the war in Italy was over. To the fury of his allies, in the March 1707 Convention of Milan Emperor Joseph gave French troops in Lombardy free passage to Southern France. A combined Savoyard-Imperial attack on the French base of Toulon planned for April was postponed when Imperial troops were diverted to seize the Spanish Bourbon Kingdom of Naples. By the time they besieged Toulon in August, the French were too strong, and they were forced to withdraw. By the end of 1707, fighting in Italy ceased, apart from small-scale attempts by Victor Amadeus to recover Nice and Savoy. Low Countries, Rhine and Danube The first objective for the Grand Alliance in this theatre was to secure the Dutch frontiers, threatened by the alliance between France, Bavaria, and Joseph Clemens of Bavaria, ruler of Liège and Cologne. During 1702, the Grand Alliance repelled an assault on Nijmegen, captured Kaiserswerth, a strong town on the eastern side of the Dutch Republic, and retook a few of the Barrier fortresses along with Venlo, Roermond and Liège.