16O'Sullivan, Jerry, and Tomás Ó Carragáin. Inishmurray: Monks and Pilgrims in an Atlantic Landscape. Cork: Collins, 2008. 33-35.
The authors note that both Wakeman (1893) and Herity (1983) suggested that the Cashel was originally a secular settlement later gifted to the Church. Finding no evidence in support of this in their excavation of several monuments outside the Cashel, the authors suggest that only excavation within the monastery wall could determine the answer. They conclude that "based upon present evidence it seems to us just as likely that it was built as an ecclesiastical enclosure."
On the other hand, Joe McGowan cites an early O.S map where there are indications of an outer concentric ring on three sides which mighty support the view that the Cashel wall is over 2,000 years old. "A series of defensive steppings on the north-western part probably completely encircled the enclosure at one time." (McGowan, Joe. Inishmurray: Gale, Stone, and Fire : Portrait of a Fabled Island. Mullaghmore, Co. Sligo: Aeolus, 1998. 20.)