Harlech Castle, located in Harlech, Gwynedd, Wales, is a medieval fortification, constructed atop a spur of rock close to the Irish Sea. It was built by Edward I during his invasion of Wales between 1282 and 1289 at the substantial cost of £8,190. Over the next few centuries, the castle played an important part in several wars, withstanding the siege of Madog ap Llywelyn between 1294–95, but falling to Owain Glyndŵr in 1404.