From the year 1757 the Irish Roman Catholics formed themselves into bodies which created terror in most of the Irish counties, but in Ulster principally, where they attacked the Protestants, firing into, and burning houses, and driving off cattle.

These societies assumed such appellations as Hearts of Oak, Defenders, Shanavists, Caravats, Threshers, Carders, United Irishmen, Whiteboys, Ribbonmen; but the Defenders and the Peep-'o-Day or Break-o-Day Boys had the largest number of members.These last societies, curiously enough, originated at Portnorris, (Mountnorris) Co. Armagh, out of a duel between a Roman Catholic and a Unitarian.

The Defenders were a thoroughly organised association, with passwords and an oath. In the year 1787 the disturbances between these latter two factions became very bitter, as the Peep-'o-Day Boys included many Unitarians and the military frequently had to be called upon to enforce peace. The religious war became so acute and riots and depredations were so common that the calendar was one continued history of indictments of treason, destruction of Protestant property, and burning outrages and murder.

In 1788 matters became more acute, and the Defenders decided not to purchase anything from Protestants, and a volunteer corps of Protestants had been raised in County Armagh and all over Ireland for national defence against French invasion. The Defenders in County Armagh (says Wright's History of Ireland) even assumed the name of Masons, and were active in attacking the houses of Protestants for arms.