Mass-rocks are among the more quietly subversive monuments in the Irish landscape, ordinary stones pressed into sacred use during the Penal Laws of the seventeenth and eighteenth centuries, when Catholic worship was suppressed under a series of legislative restrictions and priests faced imprisonment or worse for celebrating Mass. With no churches available, congregations gathered in remote fields, on hillsides, and in sheltered hollows, using a suitably flat outcrop as the focal point of the liturgy. The rock at Brackloon is one of hundreds recorded across the country, each one a marker of a community that continued to practise its faith out of doors and out of sight.

The Penal Laws, enacted in the decades following the Williamite Wars, prohibited Catholic clergy from performing their duties openly, which meant that Mass was often said at dawn or in poor weather, with lookouts posted on surrounding high ground to watch for soldiers or informers. The congregation would kneel on the bare earth or grass around the rock, and the priest would face the same direction as his parishioners rather than standing before them as in a formal church setting. Over time, as enforcement became more erratic and eventually ceased, purpose-built Catholic churches began to reappear across Ireland, and the old Mass-rocks were largely abandoned to the fields and woods where they had always stood. Many were forgotten entirely; others, like the one at Brackloon, were recorded and noted as monuments, small physical reminders of a period when the practice of religion required a degree of concealment and considerable nerve.