The ports of Essex became increasingly important for both trade and defence. Harwich in particular was a key port, and the defences, which had fallen into disrepair by 1625, were improved and repaired so that it could serve as a dockyard, a shipyard and a port. Many ships were built at Harwich but little evidence of this remains except the wooden crane of 1667.
Britain was at war frequently during the Stuart period, with the French, Spanish and Dutch being the main opponents. A Dutch attack in 1667 inspired the remodelling and rearming of Tilbury fort, and others like it along the Thames estuary, the gateway to London.