Chepstow Castle occupies a spectacular defensive position on vertical cliffs above the River Wye. It has its origin in the early Norman period when William fitzOsbern, Earl of Hereford from 1067, had juristiction over the area, and is the most southerly of a chain of fortifications along the Welsh March. The great tower may have been commissioned by William I during his visit to South Wales in 1081.
The castle remained unaltered until 1189, when it passed by marriage to William Marshal - at that time one of the most powerful men in the country. Marshal remodelled the castle from the early 1190s until his death in 1219. His revolutionary additions and modifications include the construction of a new gatehouse, the creation of the lower and middle bailey defences, the heightening of the upper bailey curtain and a brand new tower in the South West corner. Later, in the thirteenth century, Roger Bigod, the fifth Earl of Norfolk, transformed Chepstow into a palatial stronghold by building a range of accommodation and service rooms. He also created a massive tower at the south-east corner, Marten’s Tower, and an extension of the upper storey of the great tower. Considerable repair work was required throughout the Civil War as the Castle was garrisoned on a number of occasions.
Source: Turner, R. 2008. Chepstow Castle: CADW
M. Lloyd Davies, RCAHMW, 22 October 2008.