The castle was then rebuilt in stone by Gilbert de Lacy after 1148, who also established the adjacent town to help pay for the work.

[3] Following Welsh attacks, Walter abandoned Pont Hendre and instead started to build a castle at Longtown, on the site of the old Roman fort.

[8] Two circuits of earthworks to the north and south of the castle, possibly with wooden palisades, enclosed the early settlement of Longtown.

[1] Gilbert probably then rebuilt the castle in stone, at a considerable cost of £37, financed by the construction of a new borough alongside it.

[11] The stone keep was constructed in the form of a circular great tower, with walls 5-metre (16 ft) thick and three turrets spaced evenly around the outside and a hall on the first floor.

[14] The stonework is made up of sandstone rubble with cut ashlar detailing; the walls are around 4-metre (13 ft) thick, but the keep's foundations are extremely shallow.

On Theobald's death, the castle passed to his son Theobald de Verdun, 2nd Baron Verdun, who died in 1316 without surviving male heirs, whereupon the castle became part of the inheritance of his 2nd daughter Elizabeth and by right of his wife passed to her husband Bartholomew Burghersh, 1st Baron Burghersh.

[19] After the Black Death the town's population fell away sharply as well, the protected area north of the castle was abandoned, and by the 16th century it was no longer a functioning trading centre.

[23] It was in a poor condition and extensive restoration work was carried out, including the removal of many of the buildings that had encroached on the walls.

[24] In the 21st century, the central parts of Longtown Castle, including the ruined keep, the internal gatehouse and fragments of the curtain wall, are maintained by English Heritage as a tourist attraction, although the wider earthworks lie on common land.