Lancaster Castle is a medieval castle and former prison in Lancaster in the English county of Lancashire. Its early history is unclear, but it may have been founded in the 11th century on the site of a Roman fort overlooking a crossing of the River Lune. In 1164 the Honour of Lancaster, including the castle, came under royal control. In 1322 and 1389 the Scots invaded England, progressing as far as Lancaster and damaging the castle.