Lancaster Castle was originally a late 11th century earth and timber ringwork fortress, founded by Roger de Poitou. Built within the Roman fort of Lunium, King Henry I founded the stone enclosure castle, in the early 12th century. Occupied by King David of Scotland in the mid 12th century, it was retaken by Hubert de Burgh in 1199, only to be partly destroyed in the raids by King Robert the Bruce, in 1315 and 1322. The curtain wall, is flanked by a large square four storey keep and next to John of Gaunt's monumental 15th century gatehouse, is the square Norman Well Tower, were the Pendle Witches where held. Used as a prison since 1745, the 20th century, construction of the Shire Hall and court complex, considerably altered the castle. 3 miles north-east is Castle Hill.