The town was given its first charter defining it as a borough by Archbishop Donat O'Lonargan in 1212 (Finn, 1930) and probably developed into a medieval town in the period 1250-1350 (Thomas 1992, Vol. 1, 153). The enclosing town wall in Cashel appears to be a later development than the town itself in that the wall construction was begun in 1303 with the assistance of a murage grant (Thomas 1992, Vol. 2, 47). The whole town appears to have been enclosed by a wall by 1320 (Gleeson 1927, 234), and this wall would have been repaired up to the 18th century.
The wall enclosed an area of 15.5ha and was originally 1550m long. Five gates punctuated the wall circuit, and these controlled access into the town. The site of archaeological investigation was on the southern section of the walled town, and the wall here is aligned roughly south-west/north-east. The wall is constructed from roughly coursed limestone blocks with a rubble core and has an average height of c. 3m. It is in relatively good condition, but sections of the inner (north) face have collapsed and are unstable. A sally-port was recorded along this stretch of wall by Wyse Jackson (1949, 24), although its precise location is unclear. The wall has been breached within the area under investigation and was recently filled in with modern concrete blocks. This breach is almost opposite the narrow William Street, which is at a right angle to the main street and turns again at a right angle towards the east, to link into John's Street. William Street may be an original medieval laneway, and its southernmost side is c. 50m from the inner face of the town wall.
According to the Corporation Books (Thomas, 1992), trees were planted in 1702 'in the most convenient part of the Green, adjacent to the town wall', and this was presumably in the field within the town wall where the hospital extension is built. In 1704 permission was granted to Alderman Thomas Chardwick 'to make a door through the town wall' into this garden. This new entrance into the medieval town may lie where the wall has recently been rebuilt, as there is no other apparent break along the wall in the area of the Green. The door was supposedly 8ft (c. 2.4m) wide (O'Keeffe 1995, 164). The creation of a new 'door' through the wall also suggests that the walls were redundant in terms of defence. The area between the walls and the ends of the burgage plots appears not to have been developed until recent times.