Its position on the estuaries of the Stour and Orwell rivers, with its usefulness to mariners as the only safe anchorage between the Thames and the Humber, led to a long period of civil and military maritime significance. The town became a naval base in 1657 and was heavily fortified,Trollope, C., "The Defences of Harwich", Fort (Fortress Study Group), 1982, (10), pp5-31 with Harwich Redoubt, Beacon Hill Battery, and Bath Side Battery.
