Tenby is a walled seaside community in Pembrokeshire, Wales, on the western side of Carmarthen Bay. Tenby is a local government community. Remarkable functions include 2 1/2 miles (4.0 kilometres) of sandy beaches and also the Pembrokeshire Coast Course, the 13th century middle ages town walls, including the Five Arcs barbican gatehouse, Tenby Museum as well as Art Gallery, the 15th century St. Mary's Church, and also the National Trust's Tudor Merchant's House. The town is served by Tenby railway station. Watercrafts sail from Tenby's harbour to the overseas reclusive Caldey Island. St Catherine's Island is tidal as well as has a 19th century Palmerston Fort. With its strategic setting on the far west coastline of Britain, and also a natural protected harbour from both the Atlantic Ocean and the Irish Sea, Tenby was a natural settlement point, most likely a hill ft with the mercantile nature of the settlement possibly developing under Hiberno-Norse influence. The earliest recommendation to a negotiation at Tenby remains in "Etmic Dinbych", a rhyme most likely from the 9th century, protected in the 14th century Book of Taliesin.