Mulhuddart Parish has its origins in medieval times. One of the townlands in the area is associated with the name of the first Baron of Castleknock, Hugh de Tyrell. His son Richard gave the land in Castleknock (on which St. Brigid’s Church now stands) to the Benedictines from the Priory at Little Malvern in Worcestershire. Since the early 13th Century, the Chapter of Saint Patrick’s Cathedral has included two prebendaries of Castleknock, one referred to as Castrum Knock ex parte cantoris (funded by tithes from Castleknock Parish) and the other known as Castrum Knock ex parte decani (income from the tithes of Mulhuddart Parish). In 1260, the first recorded Prebendary of Mulhuddart was William de Northfield.
In 1718 the Vicar of Castleknock, Archdeacon Thomas Walls, reported to the Archbishop that Mulhuddart Church had been in ruins for many years. The Church of that time, still in ruins, is adjacent to the new cemetery at Mulhuddart, opposite the well that gives the locality its name Ladyswell. It was this well that also gave its name to the Guild of the Blessed Virgin Mary which was founded in the 23rd year of the reign of Henry VI by Act of Parliament.. The desire to have a new place of worship surfaced again in the 1860’s. On 4th March 1869, the Archbishop of Dublin, in response to a petition from the Rev. George Ayres, Prebendary of Mulhuddart, licensed a house called Larch Grove as a place of worship until such time as a new Parish church could be built. The foundation stone was laid on 28th December 1870 (the Feast of Holy Innocents). The architectural drawings were signed by the well-known firm of Welland and Gillespie. Less than a year later, on 6th November 1871, the Churchwardens petitioned Archbishop Richard Chevinex Trench to consecrate the new church. The consecration took place on 19th December 1871.
St Thomas’ does not have electricity. We therefore worship there by candlelight (and wrapped up warm), but the atmosphere makes for a special feeling in evening services, weekly in the summer and monthly throughout the rest of the year. The Easter Egg Hunt in the church’s grounds on Easter Eve, prior to the lighting of the fire and the Paschal candle, is also a special event for the church.