From 933 until 1204 the Channel Islands belonged to the Duchy of Normandy. When Normandy was lost to France during the reign of King John, Jersey chose to remain loyal to the English Crown. This act of allegiance resulted in the coastline of Jersey becoming heavily fortified as it sought to defend itself from its new enemy and closest neighbour only 14 miles from the island.
On the north coast, cliffs provided a natural defence but the bays of the east, west and south coasts were vulnerable to potential invaders. In 1781, 600 French troops landed at La Rocque and marched unchallenged to the capital, St.Helier, forcing the Lieutenant-Governer to surrender. After defeating the invaders at the Battle of Jersey bolstering the coastal defences became a priority.
Built in 1782, this granite tower is a mile off the southeast corner of the Island at La Rocque.
It replaces an earlier tower on the same spot and is named after the island's Governor, General Sir Henry Seymour Conway. However round towers were later regarded as stronger than square ones and the first and last square tower to be built in Jersey was Seymour Tower.
Jersey has one of the largest tidal movements on earth, rising and falling by about 40ft (12m) with the island's landmass increasing by a third at low tide so the troops who were stationed here until 1945 were completely marooned at high tide.