The discovery of the Bronze Age Boat shows that Dover has been involved in cross-channel traffic for at least 3,500 years. These early seafarers would not have had a harbour as we know it, instead they would have taken advantage of the mouth of the river Dour, running between its protective cliffs, pulling their boats up onto the muddy banks. Dover's sheltered position, and the fact that it is the closest land in Britain to continental Europe, was not lost on the Romans who built a harbour in the area of what is now the Market Square. On the cliffs either side of the town they built massive lighthouses to guide ships into the port at night. The Roman fleet in Britain, the ClassisBritannica, used Dover as its base.By the time of the Norman conquest the mouth of the Dour had changed and the old Roman harbour silted up. A delta of mud had divided the mouth of the river in to two streams, the Westbrook, flowing into the western side of the bay, and the Eastbrook, emptying into the sea by the cliff on which the Castle stands. The mouth of the Eastbrook became the harbour proper, called Warden Down, it was a flourishing community of seafarers, fishermen and shipbuilders. The little port was in constant danger of silting up and its life was finally ended when a fall of chalk from the cliffs blocked the river in the late thirteenth century.Lack of a safe anchorage was particularly serious as Sandwich, formerly the port for the Royal Fleet, was silting up too. For the first time people began to apply themselves seriously to the task of making Dover more than just a minor shelter for shipping. Dover also had its position as a Cinque Port to consider and all the privileges that went with it. Efforts now concentrated on the sheltered indentation made by Archcliffe to the west of the town.At the foot of Archcliffe, a stretch of mud and shingle had formed over the years forming a pool open to the sea which was deep enough to shelter ships. In 1495 Sir John Clark, a priest and Master of the MaisonDieu, built the first of the piers at Dover in an effort to provide better shelter to ships. The haven was a blessing to the community, especially in stormy weather, and hence was called Paradise.For a while all was well but soon shingle began to build up against the western side of the pier and eventually to creep around the end, threatening to block the harbour. Henry VIII funded further work on the harbour to keep it open to shipping but by 1556 Paradise was all but filled up and useless to shipping. In 1575 the town petitioned Queen Elizabeth I and a commission was set up to consider the best way to restore the harbour. William Borough, Comptroller of the Navy and chairman of the commission, recommended the building of a completely new harbour guarded at its mouth by two jetties. Bearing in mind the fate of Paradise he also advised the provision of a large pool of pent-up water, which could be released using sluices to flush out any obstructing shingle from the entrance. Under the direction of William Digges the works that were to form the nucleus of the present Dover Harbour were undertaken. In 1606 a Royal Charter was granted creating the Dover Harbour Board to administer the harbour. Now any revenue earned by the port could be ploughed back into its maintenance and development. By the terms of the Charter, not only were the harbour and pent made over to the Board but also reclaimed land up to the cliffs below Snargate and along the shore as far as the Castle should belong to it. The more land that was reclaimed, the more houses there would be, and so more rents to swell the Board's income. Through the 17th and 18th centuries a constant battle against the blocking of the harbour by shingle was fought, with numerous pleas to Parliament for funds to help pay for the work. What was really need was a jetty to the west of the harbour entrance that reached out into deep water to stop the shingle piling up against it and creeping around the end to block the harbour. The massive outer harbour we can see today owes its origin to a recommendation made in 1845 to construct a harbour of refuge capable of handling up to 20 large naval vessels. A start was made in enclosing the bay, beginning with the south western quarter because of its vulnerability to storms. The AdmiraltyPier was begun in 1847 and by 1850 had reached 650ft from the shore, ending the menace of drifting shingle. Extension work continued until 1875 when the Admiralty, put off by the cost, lost interest in the harbour of refuge. Dover Harbour Board then decided to complete the inner harbour itself and began the Prince of Wales Pier in 1892, only for the government to decide to complete the outer harbour, which it did in 1909. It is within this square mile of enclosed water that subsequent development has taken place. In the Western Docks the "railway age" harbour developed with the new Marine Station opening in 1920 and the Train Ferry Dock in 1936. In the 1950s the Eastern Docks started to be developed for the growing roll-on roll-off car ferry services. In the late 1960s a regular hovercraft service was started from a purpose built Hoverport. As the car ferry services increased the Eastern Docks continued to expand. In the 1970s the Hoverport moved to the Western Docks increasing available space for ferry berths. As the numbers of train passengers declined the Marine Station closed and was redeveloped in 1994/5 as a cruise liner terminal. This terminal was so successful that in 2000 a second cruise terminal opened. In the inner harbour too, as traditional commercial shipping use declined, the Harbour Board has encouraged new uses with the Marina in the Granville and Wellington Docks and the retail development at De Bradelei Wharf. The latest plans for the redevelopment of the Western Docks were unveiled in early 2014. These plans will involve changes to the location of the Marina and new berths on the site of the old Hoverport.