After the Norman invasion of Wales in the 11th century, a castle was built at Abergavenny; this included a relatively small, walled town.

[1] This town had a rectangle of wooden walls, protected by a V-shaped ditch, stopping just short of the modern Cross Street.

[2] In the 12th century this ditch was filled in, possibly because of a pressure on land in the town, and the town of Abergavenny then appears to have lacked any defences until the late 13th century.

[1] In the late 13th century a larger town wall was built around Abergavenny in stone, forming an oval shape, approximately 350 m by 215 m across.

The wall was paid for and maintained by murage, by which the king allowed a city to raise taxes on the imports of particular goods.