Moriarty, Thaddeus (Tadhg Ó Muircheartaigh) (c.1603–1653), Dominican priest and prior of Tralee, was a native of Castle Drum, Co. Kerry, on the Dingle peninsula. His family were the ancient lords of Aos Aisde along the banks of the River Mang. Moriarty's father was said to be the head of the local Moriarty clan.
Moriarty entered the Dominican order at its house in Tralee. He then travelled to Spain in the 1620s where, with Terence Albert O'Brien (qv), he studied at the studium generale of St Peter Martyr in the imperial city of Toledo; he later went to the Irish Dominican college at Lisbon, where he lived with Dominic O'Daly (qv). On his return to Ireland he was noted for upholding papal authority, which made him obnoxious to many protestants. He had already been awarded the sacrae theologiae praesentatus degree by 1636, when, with twelve other Dominicans, he was associated with the diocese of Ardfert. He had been advanced to the mastership in theology by 1644, when the general chapter of Rome approved his appointment as a judge of questing limits of Dominican houses in Munster. He was prior of Tralee in 1651 when Charles Sughrue presented to the convent a small graceful silver chalice, bearing Moriarty's name and sacred engravings. The portable chalice, which unscrewed into two parts, was a telling commentary: the convent of Tralee was then in ruins, and several Dominicans, supposedly traders, were actively ministering as priests, especially in the Castlemaine, Kilclohane, and Milltown region, south of Tralee behind the Slieve Mish mountain.
Following betrayal of the location of the Kilclohane Mass rock site, Cromwellian troops swooped on the assembled congregation on 15 August 1653, arresting Moriarty and, according to tradition, his brother-in-law Piaras Feiritéir (qv), scion of an old Norman family settled near Dingle and an accomplished Kerry poet. Moriarty and other notables were transported to Loch Leane and across the lake to Ross castle. Condemned to death by the Cromwellian governor of Killarney, Moriarty and his companions, including Feiritéir, were publicly hanged on 15 October on the site latterly occupied by the market square and Killarney's modern Franciscan church. A Portuguese source, a list of alumni (before 1664) of the Irish Dominican Corpo Santo College, Lisbon, mentioned him as one ‘who had suffered martyrdom’.
Thaddeus Moriarty's brother, Thomas, was also a Dominican and ministered amid persecution in Kerry and further afield. Three of their contemporary kinsmen were Dominicans too and priestly academics at Lisbon. Murtagh Moriarty (d. c.1672), recorded in c.1636, was a filius of Tralee, had been educated in Portugal, and had a career as a distinguished professor of theology in the Royal College of São Domingos in Lisbon. Thaddeus Moriarty (Thaddeus a S. Thoma), likewise educated in Portugal, became ‘deputed regent of studies’ of the same college and was promoted sacrae theologiae praesentatus at the general chapter of the order held at Lisbon in June 1650. Hugh Moriarty, Dominic of the Rosary, was so styled by the general chapter of 1650, which awarded him the degree sacrae theologiae praesentatus; he was probably rector of Corpo Santo college in the 1650s and again in 1664–6, and was still at Lisbon in 1679–80.