Thomas Betagh was a Jesuit priest and an educationalist. The Betagh family were an Anglo-Norman family who held lands at Laurencetown outside Kells in the early 1640s. After the Cromwellian settlement the head of the family Francis Betagh of Moynalty was dispossessed of his lands, left Ireland to go and fight in the Irish Brigade in France.

Thomas Betagh was born in 1736 in Kells. His family were tanners who later moved to Dublin. Betagh received his early education in Kells. After continuing his education at Saul’s Court, the Jesuit school in Dublin, Thomas was sent to a Jesuit seminary in France. Arriving in France at the age of fourteen Betagh studied at Nancy. Ordained into the Jesuit order, Betagh became  professor of classics at the French seminary. He returned to Ireland where he taught at Saul’s Court in Dublin. After the Jesuits were suppressed in 1773 he became a secular priest. He established  a number of free schools for poor boys. Betagh took an interest in his old town and diocese. In 1779 he wrote to Valentine Plunket of Kells to congratulate him on the appointment of his brother, Patrick, as bishop of Meath. Betagh had been born in the same year as the bishop and they were friends growing up in Kells. They were still corresponding in 1779. By 1784 Betagh was in charge of Saul’s Court and the school had a huge influence on the emerging Church when the Penal Laws were being relaxed. Betagh nourished the vocation of Catherine McAuley who later founded the Sisters of Mercy. A painting of Betagh is located in the convent on Baggot Street.  Betagh became parish priest of St. Michael and St. John in 1799 and laid the foundation for the new church in 1810. Betagh died a year later.