The Irish name Ráth Mhaighe Deiscirt, meaning Fort of the Southern Plain, points to a settlement of some age, and scholars have suggested the site may be roughly contemporary with Rattoo, a foundation associated with Bishop Lugach in the sixth century. That would make these stones, or at least the ground beneath them, among the oldest Christian sites in Kerry.

The political moment that brought Ratass briefly into prominence came in 1111, at the Synod of Rathbreasail, a landmark church council that attempted to impose a coherent diocesan structure across Ireland. The assembled bishops chose Ráth Mhaighe Deiscirt, identified as being near Ardfert, as the episcopal see of Kerry. The reason Ardfert itself was passed over appears to have been practical rather than theological; the town had been destroyed not long before 1111 by warring factions, and was presumably in no condition to serve as a cathedral centre. The decision, however, did not hold. Ardfert recovered its standing and became the permanent seat of the bishops of Kerry regardless. By 1117, Anmchidh Ó hAnmchada is recorded as dying in the role of Bishop of Ardfert, suggesting the short-lived elevation of Ratass had already been quietly set aside. It is a peculiar footnote: a place chosen, on paper, to anchor an entire diocese, and then simply passed over as circumstances shifted.