Dover Castle

Dover Castle is a medieval castle in Dover, Kent, England and is Grade I listed. It was founded in the 11th century and has been described as the "Key to England" due to its defensive significance throughout history. Some writers say it is the largest castle in England, a title also claimed by Windsor Castle. This site may have been fortified with earthworks in the Iron Age or earlier, before the Romans invaded in AD 43. This is suggested on the basis of the unusual pattern of the earthworks which does not seem to be a perfect fit for the medieval castle. Excavations have provided evidence of Iron Age occupation within the locality of the castle, but it is not certain whether this is associated with the hillfort. The site also contains one of Dover's two Roman lighthouses (or pharoses), one of only three surviving Roman-era lighthouses in the world, and the tallest and most complete standing Roman structure in England. It is also claimed to be Britain's oldest standing building. Built in the early 2nd century, the 5-level 8-sided tower was made of layers of tufa, Kentish ragstone, and red bricks. The castle lighthouse survived after being converted into a belfry in the Saxon era (1000), having a new upper layer added (1430), and was partially renovated in 1913–1915. The scant remains of the other Roman lighthouse, known as the Bredenstone or the Devil's Drop of Mortar, are located on the opposing Western Heights, across the town of Dover. The Roman lighthouse at Boulogne-sur-Mer across the Channel survived for many centuries, and its light should have been visible from Dover. It was built circa AD 39 by order of the Emperor Caligula, possibly in preparation for an invasion of Britain. Suetonius refers to Caligula's "erection of a tall lighthouse, not unlike the one at Pharos, in which fires were to be kept going all night as a guide to ships". Known as the Tour d'Ordre, coastal erosion led to it toppling into the sea in 1644. Engravings of its height may show how the Dover Roman lighthouse once looked.