Excerpts from Books and Wikipedia
"In 1800, following the Irish Rebellion of 1798, the Irish and the British parliaments enacted the Acts of Union. . . . Part of the agreement forming the basis of union was that the Test Act would be repealed to remove any remaining discrimination against Roman Catholics, Presbyterians, Baptists and other dissenter religions in the newly United Kingdom. However, King George III, invoking the provisions of the Act of Settlement 1701 controversially and adamantly blocked attempts by Prime Minister William Pitt the Younger. Pitt resigned in protest, but his successor Henry Addington and his new cabinet failed to legislate to repeal or change the Test Act. This was followed by the first Irish Reform Act 1832, which allowed Catholic members of parliament but raised the property qualification to £10 effectively removing the poorer Irish freeholders from the franchise. . . . The continuing obligation of Roman Catholics to fund the established Church of Ireland, however, led to the sporadic skirmishes of the Tithe War of 1831–38. The Church was disestablished by the Gladstone government in 1867. " [Wikipedia]