In the 1660s Harwich became an important naval base and dockyard. In 1667, because of the Dutch Wars, it was decided to replace the medieval town wall with a turf bank, enclosing both the town and the Navy Yard. The Navy Yard closed in 1713, although ship-building continued on the site under private ownership until 1827. The other industries, such as fishing and trade continued, there was a regular cross-channel service to the Low Counties and in the nineteenth century the septaria mines at Dovercourt were re-opened. The Napoleonic Wars brought further defensive measures to Harwich, including the Redoubt. In the 1890’s the Beacon Hill fort was built and the town was to play an important role as a naval base in both the First and Second World Wars.