The term Catholic unionist has become controversial since the start of the 1970-1998 Troubles, due to the strong association of Ulster Unionism with Protestantism.
Roman Catholic support for the Kingdom of Ireland (1542-1800) had the full backing of the Holy See from 1555, with the papal bull Ilius per quem issued by Pope Paul IV during the reign of Queen Mary.
In general, the Holy See had better relations with Europe's monarchies, particularly Spain, Austria, France and Portugal, and was seen as a conservative force.
Irish Catholic unionists petitioned against the Government of Ireland Bill 1893 on the grounds that it would create a "revolutionary spirit disastrous to the true interests" of Catholicism.
[5] The most notable murder was in June 1922, when a local magistrate James Woulfe-Flanagan was shot dead in front of his family while leaving Mass at Newry Cathedral.
The British diplomat to the Vatican at the time was John Francis Charles, 7th Count de Salis-Soglio, who owned large landed estates in Limerick and Armagh.
Many prominent members of the Alliance Party of Northern Ireland have been Catholics, including the majority of its past leaders (such as John Cushnahan, Oliver Napier and Seán Neeson), some of its Deputy Leaders (such as Seamus Close and Eileen Bell), former MP (of the Northern Ireland Parliament) Thomas Columba Gormley, as well as three of its seven current Assembly members.