The original Holy Trinity Church of Ireland parish was consecrated by Bishop Mant on Tuesday 17th January 1843. The church was built in the Gothic style and was noted for its graceful spire. Inside the most noticeable feature was the three-decker pulpit. Belfast was a city of 20,000 people in 1843. Holy Trinity was to serve its parishioners for 98 years. On Tuesday 15th April 1941 the death blow was struck by German bombs when the church was destroyed. This was the same fate as St Silas and many others especially in the north side of the city.
After the war it was decided not to rebuild the new Holy Trinity on its original site as there was no longer the population to sustain it. The area had changed radically and was now more industrial than residential. However the local Bishop wrote at the time, “I think the name and the traditions of the church should be preserved in other circumstances. There are suburbs growing around the city… to one of these the church should be moved. In a new environment its splendid history could be repeated.”
The new area was to be within the Ballysillan area of north Belfast, a fast expanding residential area. On 1st May 1954 the foundation stone of the new Holy Trinity was laid and on 26th May 1956 the new church was consecrated. In 1996 with the closure of St Silas it was decided to join the two into one.
The new church is a modern Gothic building based on the late English Medieval style, with particular reference to the Perpendicular period. The nave is unusually lofty, compared with modern churches. The tower rises 80 feet and the belfry houses the original church bells.
The third parish in the title is Immanuel Parish Church which serves the Ardoyne district of north Belfast. It was created in 1940 to serve the recently built new residential homes of the area. A hall served as church and hall until 1963 when the new church was built. That church still serves the area and the present rector of Hoily Trinity and St Silas is also the rector of Immanuel.