The river Medway during the Dutch attack on the English fleet, 1667, by Willem Schellinks. England's principal naval base was at Chatham on the river Medway. After reducing the fort at Sheerness, the Dutch ships sailed upstream and reached Chatham on 22 June 1667. Below left is Fort Sheerness, held by a Dutch garrison. Despite the ring of submerged ships, whose masts are visible above the water, the Dutch managed to penetrate the defences. In the distance, to the left in the background, is London. To the right in the background is Rochester.