Harlech Castle was built between 1283 and 1289 by Master James of St George, King Edward I's mason-architect. In 1286, with the work at its height, nearly 950 men were employed under the superintendence of Master James. The final result was a perfectly concentric castle, where one line of defenses is enclosed by another. Unfortunately, the outer wall is ruinous today and fails to convey the true 13th-century effect. Harlech Castle played a key role in the national uprising led by Owain Glyn Dwr. After a long siege, it fell to his forces in 1404. The castle became Glyn Dwr's residence and headquarters, and one of the two places to which he is believed to have summoned parliaments of his supporters. It was only after a further long siege in 1408 that Harlech was retaken by English forces under Harry of Monmouth, later Henry V. Source: http://www.castlewales.com/harlech.html