The castle itself is divided into an upper and a lower ward, defended by a single curtain wall with two main gatehouses, the King's Gate and the Queen's Gate.Octagonal towers protect all angles of the curtain wall.The castle, together with the walled borough (NPRN 93527), was begun in 1283 and was still incomplete by about 1330 when major work ended.It consists of seven great polygonal towers, two turrets and two great twin towered gates, all joined by massive curtain walls tracing a rough figure of eight.
The English conquest of N Wales followed quickly after the death of Llewelyn ap Gruffudd in 1282 and Caernarfon was built to consolidate the English gains.
Edward I employed James of St George as his architect, who had previously been employed by Philip of Savoy and had designed for him the fortress-palace of St Georges d'Esperanche.
James also directed the building other castles for Edward I, including Harlech, Conwy and Beaumaris, using English craftsmen and labourers.
At the other end of the castle is the mighty Eagle Tower, crowned by three tall turrets topped by sculptured figures.
The grand appartments planned for the castle interior, including a great hall, may never have been built.