Swansea Castle lies at the centre of the enclosed and ultimately walled borough and occupied an overall area of around 1.85 hectares (4.6 acres). Denied the evidence which would have been furnished by surviving fabric, it is only possible to discern two broad phases between its foundation, in or soon after 1106, and the building of the largely surviving 'New Castle' in the late thirteenth century. During the first phase, from 1106 until the early thirteenth century, the original castle (nprn 275871) was of earth and timber; in the second phase, probably between 1221 and 1284, masonry defences replaced the timber palisades of the inner castle and its bailey.
The surviving remains are primarily thirteenth and fouteenth century in date. Constructed of coursed Pennant sandstone blocks, they consist of a roughly L-shaped residential block to the southeast with a tower to the north and a section of surviving curtain wall running between the two. The residential block comprises a semicircular garderobe turret to the west, a rectangular garderobe tower to the south-east with a hall and parlour range between. The entrance to the interior is through the northern side and gives access to five basement rooms with pointed tunnel-vaults. Although the tower may represent the earliest surviving work, it has been substantially altered and evidence remains of its later use as a debtors' prison. The most prominent feature of the castle is the arcaded parapet, probably added by Henry Gower in the fourteenth century.
Sources: Cadw listed buildings database; Pevsner, 'Glamorgan', 1995, pp587-589.
RCAHMW, February 2010.