A bullaun is a large boulder or rock, usually of considerable age, into which one or more rounded depressions have been deliberately ground. The hollows, smooth-sided and basin-like, would have collected rainwater, and across Ireland such stones have accumulated centuries of folk association, sometimes linked to cursing rituals, sometimes to healing, and often to early Christian or pre-Christian sacred sites. They are common enough across the Irish landscape to seem unremarkable, yet each one represents sustained human effort and, almost certainly, sustained human belief.