[2] The site also controlled an important crossing point over the river Conwy between the coastal and inland areas of North Wales, and was defended for many years by Deganwy Castle.

[2] The English kings and Welsh princes had vied for control of the region since the 1070s and the conflict had been renewed during the 13th century, leading to Edward I intervening in North Wales for the second time during his reign in 1282.

Edward captured Aberconwy in March 1283 and decided that the location would form the centre of a new county: the abbey would be relocated eight miles inland and a new English castle and walled town would be built on the monastery's former site.

[5] Edward's plan was a colonial enterprise and placing the new town and walls on top of such a high-status native Welsh site was in part a symbolic act to demonstrate English power.

[8] Analysis of the new towns in Wales and England of the period has identified common similarities in their design, with most featuring a T-shaped street plan stretching away from the coast or river, aligned with a castle that is usually positioned at a top corner of the "T".

[10] The walls of Conwy were built at around the same time as the castle itself, under the overall supervision of Master James of Saint George, Edward's chief architect in North Wales.

[23][nb 2] Over a century later, there are records of the walls being repaired in the 1520s and 1530s by Henry VIII in preparation for a potential royal visit, but the ascension of the Tudor dynasty to the English throne had heralded a change in the way Wales was administered.

[33] The town walls were leased from Conwy's local authority by the Ministry of Works in 1953, and a concerted effort began to conserve and protect the fortifications.

[38] The walls were declared part of a UNESCO world heritage site in 1986 and are classed as a grade 1 listed building and hold scheduled monument status.

[45] Two of the towers were significantly affected by 19th-century developments; one was converted into an entrance way for the Bangor Road in 1827, whilst another suffered a deep fissure caused by subsidence from the excavation of the Chester to Holyhead railway tunnel in 1845, and had to be underpinned in 1963.

[46] The western wall originally extended out to the river Conwy itself, ending in a round tower, but this has since been lost; a similar spur arrangement was seen at Chester and Lincoln.

[50] The second gatehouse, Mill Gate, was designed to allow access to the royal watermill that lay just outside the main town, and similarly features twin protective towers.

[51] In between the two gatehouses are the remains of Llywelyn's Hall, a grand building originally built into the town walls by Edward I before being dismantled and moved to Caernarfon Castle in 1316.

[53] A unique set of twelve medieval latrines is built into the southern town walls, first constructed for the use of royal staff working in adjacent buildings in the 13th century.