Mass-rocks are among the more quietly extraordinary survivals of the Penal Law era in Ireland, a period roughly spanning the late seventeenth and early eighteenth centuries, when Catholic worship was formally suppressed under legislation that banned priests, closed churches, and made the open practice of the faith a punishable offence. Communities responded by gathering outdoors, often in remote or sheltered spots, where a priest could say Mass using a convenient boulder or prepared stone slab as his altar. The rocks themselves were chosen for concealment as much as convenience, tucked into hillsides, behind field boundaries, or close to water, places that offered both a degree of privacy and a quick means of dispersal if authorities approached.

The example at Loch An Bhuí belongs to a scattered but significant category of such sites recorded across Connacht and beyond. The lough itself, whose name translates loosely from Irish as the yellow lake, sits in a landscape that would have been familiar to generations of people for whom this kind of furtive congregation was simply the ordinary texture of religious life. The stone would have been used by a local priest serving a congregation that had no legal place of worship available to them, gathering in the open regardless of weather or season. Many such sites passed out of active use as the Penal Laws were gradually relaxed through the late eighteenth century and Catholic Emancipation arrived in 1829, after which permanent church buildings became possible again. The rocks themselves, however, often remained, quietly remembered by local communities even as they ceased to serve any liturgical function.