Canterbury is the largest settlement featured on this drawing, with barracks recorded nearby. The draughtsman has also noted two military batteries along the coast, roughly level with Sandwich. Produced against the background of the Napoleonic Wars, the Ordance Survey drawings show a clear preoccupation with defensive structures, particularly along the vulnerable south coast. On this map, Deal Castle, Sandown Castle and Walmer Castle form a line of protection for the Downs anchorage. Commissioned by Henry VIII in the late 1530s, they were built as a defence against possible invasion after his divorce from Catherine of Aragon angered French and Spanish Catholics. The draughtsman has delineated the distinctive petal formation of Deal Castle, built to resemble the Tudor Rose.