Fortification of Portsea

1665

During the seventeenth century, particularly from the 1660s onwards under Charles II, Portsmouth and Portsea were heavily fortified to protect the increasingly valuable dockyard from attack. The defences included substantial earthwork ramparts, bastions and a moat system that enclosed both the old town of Portsmouth and the newer dockyard area of Portsea. The fortification programme was driven by the growing strategic importance of the dockyard during a period of intense naval rivalry with the Dutch Republic and France. The defences were designed by military engineers following the principles of contemporary European fortification theory, with interlocking fields of fire, covered approaches and provision for artillery. Gates were built into the walls at intervals, including the Lion Gate and the Unicorn Gate, which gave their names to nearby streets and areas. The fortifications gave Portsea a distinct identity, physically separating it from the surrounding countryside and creating an enclosed, self-contained community behind the walls. Strict controls governed entry and exit through the gates. The defences were maintained and updated over the following two centuries before being largely dismantled in the nineteenth century as the town expanded beyond its walls. Sections of the fortifications survive, particularly in Old Portsmouth, and the street pattern of Portsea still reflects the line of the former defences.