Dolbadern Castle, North Wales

This is one of Turner’s early oil paintings from 1800, depicting the 13th-century Dolbadarn Castle in Llanberis, north Wales. It’s thought that Owain Goch ap Gruffydd, ruler of part of the Kingdom of Gwynedd (in modern-day north Wales) was imprisoned in this castle by his brother Llywelyn, another ruler looking to extend his kingdom in 1255. Owain spent 20 years locked up before Llywelyn reluctantly released him under the terms of a new treaty.