Hay Castle

in 1823, showing the castle overlooking the town]] The Normans began to make incursions into South Wales from the late 1060s onwards, pushing westwards from their bases in recently occupied England. Their advance was marked by the construction of castles and the creation of regional lordships. The Norman conqueror Bernard de Neufmarché conquered Brecknock in 1091 and assigned the manor of Hay to one of his followers, Philip Walwyn. The first castle in Hay, later abandoned, was built by St Mary's church outside the main settlement, where a motte known as Hay Tump still survives.

The de Braose dynasty expanded Hay Castle in stone around 1200 with a curtain wall reinforced by intramural timbers, turning the gate tower into a keep. The castle tenants used the chapel of St John in the town for their worship. During the First Barons' War, Reginald de Braose joined the alliance against King John who successfully attacked the castle in 1215. The Welsh prince Llywelyn ab Iorwerth attacked and burnt the town and castle in 1231 and the castle was then rebuilt by Henry III in 1233.

Hay Castle was substantially expanded in the 17th century, creating a Jacobean mansion. Two explanations have been offered by historians for this redevelopment. One possibility is that during the first half of the 17th century Howell Gwynne built a manor house to the west of the old keep, which was replaced by a new mansion in 1660 by James Boyle of Hereford. Another reverses this sequence, suggesting that James Boyle left the castle to Howell Gwynne in 1603, and that the mansion was built at the beginning of the century.