"That the Watch to be made upon the Sea Coast through the Realm shall be made by the Number of the People, in the Places, and in Manner and Form, as they were wont to be made in Times past and that in the same Case the Statute of Winchester[25] be observed and kept." There is every reason to believe that there was a properly organized coastguard force at a much earlier period, although precise information on the subject is not available. Certain manuscripts relating to the defence of the coast of Norfolk, however, indicate the existence of a coastguard in that county as, early as the thirteenth century.[26] In more recent times the duties of the coastguards included the suppression of smuggling and the aiding of shipwrecked vessels. Another purpose was to serve as a reserve to the navy: but in earlier times the prevention and suppression of smuggling was the main work of the coastguards. Early in the nineteenth century a coast blockade was established on the coasts of Kent and Sussex, and detachments of men and boats were stationed at the Martello Towers on the sea-coast. It is time, perhaps, to bring these pages on the coast defences of England to a conclusion, and to review very briefly the chief features of the subject. There are one or two points which stand out with peculiar prominence. Firstly we are struck by the origin, development, deterioration, and final degradation in the methods of coast defence. In the middle and later periods of the Roman occupation of Britain the fortresses for coast defence were built in massive masonry. In the earliest examples reliance was placed alone in mass and weight, and no attempt was made to protect the wall by enfilading. In the works built later on this defect was made good. Protecting bastions gave opportunity of attacking the invaders in flank, and so protecting the wall. In the Norman period, again, and particularly in its earlier part massive keeps of great strength and height were erected for the dual purpose of resisting the enemy by passive force, and of keeping a good look-out over the surrounding country or sea, by means of which movements of the enemy could be discovered. In the periods which followed, notably from the reign of Henry II to that of Richard II, the art of building castles was constantly being improved and developed. Defensive works were adapted to the new forms and methods of offence. From that time downward to the first few years of the nineteenth century there is every indication of decadence. The defences became more and more feeble. The "chain," as a serious bar to the progress of unwelcome shipping, reached its most absurd and ridiculous stage during the time of the Dutch invasion of the Medway in 1667, when the "Chain of Chatham" was snapped without the slightest difficulty by the Dutch ships.