Federico Spinola was the younger brother of Ambrogio Spinola, the famed general of the Army of Flanders, and had built his own reputation in soldiering and privateering. In 1602 he had taken his remaining six galleys from Sluis to Lisbon, refitted them, and filled their holds with the pay chests urgently needed for the Spanish armies in Flanders. At Santander he added 400 more soldiers to bring his complement to a full tercio of 1,600 men. A captured English merchant ship was dropped off at A Coruna. Then he started north. The squadron was making the same Channel run that had succeeded in 1599 - and Robert Cecil, the spymaster of Elizabeth I's late reign, knew it. Cecil had been tracking Spinola since the galleys reached Blavet in Brittany at the start of October.

A galley in the Channel is a vulnerable creature. Built long and low for ramming and boarding in flat water, its rows of oars and shallow freeboard made it murderously dangerous in the Atlantic swell that funnels through the Dover Strait. Galleys could be terrifying in a calm, but they could not absorb broadsides from sailing warships built for the rough northern seas. The enslaved oarsmen chained to the oar benches - mostly captured Moors, North African Muslims, and convicts - were powerless in any engagement. The very design that had made them dominant for two thousand years in the Mediterranean was the design that doomed them in the cold water off Dungeness. The enslaved rowers chained below decks were the first people to discover this when the shooting started.

Sir Robert Mansell commanded three English warships: the 30-gun Hope, the 42-gun Victory, and the 42-gun Answer. His flag captain guessed correctly that Spinola would try to hug the English coast for cover - the lee shore offered some protection from the prevailing weather - and Mansell spaced his three ships at intervals along the likely line of approach, with smaller flyboats running between them and a Dutch squadron under Jan Adriaanszoon Cant standing off the Flemish coast to catch anything that broke through. Cant had been sent south by Vice-Admiral Jacob van Duyvenvoorde, who had been intercepted by smallpox before he could reach Spinola himself. Just before midnight on 3 October, with the moon up, the Spanish galleys came into sight.

Mansell ordered an attack on the spread of galleys rather than concentrating fire on any single ship. Off Dungeness, the English vessels - including the smaller Moon and Samson, which had joined Mansell - blazed away at every target the moonlight showed them. The galleys, taking hits across the squadron, began to fall apart as fighting platforms. A number of the enslaved oarsmen took the chance to jump overboard. A few made it ashore in the surf and were captured and interrogated at Dover Castle - one of the rare moments in the war when the men who actually rowed Spinola's invasion squadron got to tell their own story to anyone. By the time the running fight reached Goodwin Sands, the surviving Spanish galleys had broken off and were racing for the Flemish coast and the safety of Sluis.

Mansell sailed unmolested through to Sluis, where Spinola and his five remaining galleys still represented a threat. Mansell himself was rewarded with the title Vice-Admiral of the Narrow Seas, in commemoration of the battle. The dream of a galley-borne invasion of England survived only one more year. In 1603 Spinola was caught again, this time by the Dutch blockading force off Sluis. He was mortally wounded trying to escape. When Sluis surrendered to the Dutch in 1604, the last Spanish galley base on the Channel coast went with it. Philip III's ambition of putting Spanish soldiers ashore in Kent by oar power had ended. The Anglo-Spanish War itself ended that same year with the Treaty of London. The strait would see plenty more battles - against the French, the Germans, and itself - but never again against rowed warships from the Mediterranean.