On the location of the current inner bailey, their castle at Conisbrough was most likely an earthwork enclosure or ringwork capped with a timber fence and with timber dwellings within it. There was most likely an outside bailey as well. The castle would have been surrounded by a water-filled ditch which could have been filled with water to make it more defensible. Conisbrough is a magnificent medieval fortress built around 1088 by Earl Morcar. It is one of the largest castles in North Yorkshire and has been listed as being of international importance by Historic England. The castle sits on a hill above the River Derwent with views over much of northern Yorkshire. It was built as a replacement for another castle near here which had been destroyed by Edward III in 1327 during his campaign against the Scots. The new castle was designed by Thomas de Burgh, who also did work on Caernarfon Castle further up the coast. It was probably built using materials taken from the old Scottish castle. Work started in 1088 but wasn't finished until 1225 when it functioned as both a garrison and a court of justice. By this time, Earl Morcar was dead, having been defeated and killed by Simon de Montfort at the Battle of Evesham in 1265. His son and successor, Robert, only lived for about three years after which time the throne passed to their cousin Edward I.