The Chateau de Ranton is a small fortified castle in the village of Ranton, just west of Loudun, and south of the Loire. It was one of the front-line of fortresses which were built to defend the royal city of Loundun on the border of Aquitaine at the beginning of the 'Hundred Years' War' in 1340-1345. It played this military role until 1372. It then became a feudal manor and one of the estates of aristocratic families associated with the Courts of the French Kings and the Dukes of Anjou.

The Chateau was built in a natural strong point in the landscape, and the recorded history of the area goes back much further than that of the Chateau itself. The site of the Chateau de Ranton, dominating the passage through the Dive Valley, was already a stronghold during the Merovingian period. Little stone was yet used for building, and any fortifications would have been of wood. There were many such forts in the area; one at Loudun itself and another is known to have existed at Pouant; the high point between Loudun and Richelieu. At Ranton, the beginnings of the moat may already have been excavated. In fact, the earliest of the extensive network of passages excavated in the limestone around the moat date from the Merovingian period and the 9th century when the limestone outcrop housed a refuge from the Viking raids up the Loire and Vienne. Traces of the characteristic architecture still exist: the sloping stone roofs at weak points in the rock are typical of this period. This collection of notes about the area – about the people, places and events that have marked the area – therefore begins in the Roman period and extends through the early Middle Ages, as well as during the period of the Chateau's recorded history.

The buildings of the Chateau de Ranton inside the main rampart wall were re-built in the 16th century in the Renaissance style, as the home of a series of protestant families in the French Wars of Religion. It escaped destruction both by Cardinal Richelieu in the early 17th Century and again in the French Revolution, but was little more than a ruin by the 1940s. It has been restored in three phases since 1950, and now is one of the most complete fortresses of the 14th century left in France.