In 1702, the opening year of the War of Spanish Succession, a powerful fleet of Anglo-Dutch warships was assembled under Admiral Sir George Rooke, as Commander-in-Chief, to attack and capture Cadiz. Some footholds were gained near the city but after six weeks of vacillation the allied fleet retired ignominiously on 18th September. The prospect of returning empty-handed must have been daunting to Rooke. On his homeward journey he learned of a valuable Spanish treasure fleet that had anchored at Vigo Bay in north-west Spain. Rooke arrived to discover that Chateaurenault, the French admiral, had laid a boom defence of masts across the inner harbour, covered by guns from sea and land, and had positioned his largest men-of-war to cover it. Admiral Thomas Hopsonn, aboard his flagship 'Torbay' (80 guns), was ordered to break the boom while the Duke of Ormonde's troops assaulted the forts. The Anglo-Dutch fleet followed astern of Hopsonn, capturing every ship not already burnt by the French, along with considerable treasure.