Castillion-sur-Agen was a medieval castle

Castle

A castle is a type of fortified structure built in Europe and the Middle East during the Middle Ages by European nobility. Scholars debate the scope of the word castle, but usually consider it to be the private fortified residence of a lord or noble...

 in the commune of Bon-Encontre

Bon-Encontre

Bon-Encontre is a commune in the Lot-et-Garonne department in south-western France....

, near Agen

Agen

Agen is a commune in the Lot-et-Garonne department in Aquitaine in south-western France. It lies on the river Garonne southeast of Bordeaux. It is the capital of the department.-Economy:The town has a higher level of unemployment than the national average...

 in Aquitaine

Aquitaine

Aquitaine , archaic Guyenne/Guienne , is one of the 27 regions of France, in the south-western part of metropolitan France, along the Atlantic Ocean and the Pyrenees mountain range on the border with Spain. It comprises the 5 departments of Dordogne, :Lot et Garonne, :Pyrénées-Atlantiques, Landes...

, France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

.

Built on the top of a small hill with sheer rock cliffs (the plateau de Castillou), it was "fortified by both nature and artifice". According to the 12th-century chronicler Robert of Torigny, Henry II of England

Henry II of England

Henry II ruled as King of England , Count of Anjou, Count of Maine, Duke of Normandy, Duke of Aquitaine, Duke of Gascony, Count of Nantes, Lord of Ireland and, at various times, controlled parts of Wales, Scotland and western France. Henry, the great-grandson of William the Conqueror, was the...

 besieged

Siege

A siege is a military blockade of a city or fortress with the intent of conquering by attrition or assault. The term derives from sedere, Latin for "to sit". Generally speaking, siege warfare is a form of constant, low intensity conflict characterized by one party holding a strong, static...

 Castillion-sur-Agen in 1161. After just one week the garrison capitulated. Roger of Howden recorded that nearly 15 years later, in 1175, the site was besieged by Prince Richard

Richard I of England

Richard I was King of England from 6 July 1189 until his death. He also ruled as Duke of Normandy, Duke of Aquitaine, Duke of Gascony, Lord of Cyprus, Count of Anjou, Count of Maine, Count of Nantes, and Overlord of Brittany at various times during the same period...

 (later King Richard I of England), Henry II's son. On this occasion the siege lasted two months; it was part of a campaign of repressing rebellious barons after the Revolt of 1173–1174. It was Richard's first successful siege.