Construction of Denbigh Castle began in October 1282 after Denbigh was granted to Henry de Lacy, Earl of Lincoln. At the outset, the hilltop was enclosed with stout curtain walls and half-round towers to protect the town. Further developments to the castle were restricted by the Welsh Revolt in 1294 and led to the construction of a much higher curtain wall with polygonal towers and a massive three-towered gatehouse. The castle and its defences experienced a number of tests most notably an attack by Owain Glyn Dwr in 1400, and it was burned down in 1468. The castle was also affected by the War of the Roses between 1455 and 1485. Robert Dudley, who later became Lord Leicester repaired the residential parts of the castle and also erected a large new church. Denbigh Castle was held for the King by Colonel William Salesbury during the Civil War between 1642 and 1648, and after defeat, later in 1660 the castle was deliberately slighted and rendered useless. The castle was then left to ruin.

Source: Butler, L.A.S. 2007. Denbigh Castle: Cadw

M. Lloyd Davies, RCAHMW, 22 October 2008