From Stamps of the World
There has been a settlement in this location since the Mesolithic era. A nunnery was founded by Eanswith, daughter of Æthelberht of Kent in the 7th century, who is still commemorated as part of the town's culture. During the 13th century it subsequently developed into a seaport and the harbour developed during the early 19th century to provide defence against a French invasion, and expanded further after the arrival of the railway in 1843.
The harbour's use has diminished since the opening of the nearby Channel Tunnel and stopping of local ferry services, but still remains in active use.Until the 19th century Folkestone remained a small fishing community with a seafront that was continually battered by storms and encroaching shingle that made it hard to land boats.
In 1807 an Act of Parliament was passed to build a pier and harbour which was built by Thomas Telford in 1809. By 1820 a harbour area of 14 acres (5.7 hectares) had been enclosed. Folkestone's trade and population grew slightly but development was still hampered by sand and silt from the Pent Stream. The Folkestone Harbour Company invested heavily in removing the silt but with little success. In 1842 the company became bankrupt and the Government put the derelict harbour up for sale. It was bought by the South Eastern Railway Company (SER), which was then building the London to Dover railway line. George Turnbull was responsible in 1844 for building the Horn pier. Dredging the harbour, and the construction of a rail route down to it, began almost immediately, and the town soon became the SER’s principal packet station for the Continental traffic to Boulogne.