William Borlase first recorded this stone structure as a dolmen in 1897, and it continued to be listed as a megalithic monument by antiquarians Lord Killanin and Michael Duignan through the 1960s. However, local memory preserved in the Ordnance Survey Name Books reveals its true purpose: this wasn’t an ancient burial site at all, but rather a Mass rock altar used during Ireland’s Penal Laws era.

During the late 17th and 18th centuries, the Penal Laws severely restricted Catholic worship in Ireland, forcing priests and their congregations to celebrate Mass in secret outdoor locations. These clandestine gathering spots, known as Mass rocks or Mass stations, were often simple stone altars set up in remote areas where lookouts could warn of approaching authorities. The Cloghan More altar served this vital role for the local Catholic community, providing a place of worship when their faith was effectively outlawed.

The altar remained in use until around 1845, when it was dismantled, likely coinciding with the gradual relaxation of anti-Catholic legislation following Catholic Emancipation in 1829. Its misidentification as a prehistoric monument is hardly surprising; many Mass rocks were deliberately constructed using ancient stones or built near existing archaeological features to provide cover for their true purpose. The confusion persisted well into the 20th century, with the site appearing in archaeological surveys until local oral history corrected the record in the 1904 Ordnance Survey revision.