St. Colman of Dromore, County Down, set up a small 'daub and wattle' church on this site in 510 AD. Probably thatched with reeds from the River Lagan which flows beside it, this church site has been, for the 15 centuries since, a location for the worship of Jesus Christ, the Redeemer of all humanity. Little evidence is available for the first 700 years of St. Colman's Church nor is there any indication of either its style or size.

In the twelfth century the English King Henry II revised a system of dioceses and bishops which covered the whole of Ireland. One of those dioceses, named DROMORE, took as its base this Cathedral Church. There had been bishops and abbots of Dromore before then, but from this time the history becomes more complete. A medieval church, about which no record exists, was destroyed in the late 1500's. It was James I who, in 1609, issued Letters Patent giving the Church of St. Colman a new title and a new status: the Cathedral Church of Christ the Redeemer Dromore.

That building was destroyed in 1641 and a new structure, of which small portions are still visible was built by Bishop Jeremy Taylor in 1661. A narrow structure, about 20 feet wide, 100 feet long was first built. It forms the base of the current Tower Aisle. A Tower was built and soon dismantled. The Percy Aisle was added by Bishop Thomas Percy in 1811. It sits at right angles to the Tower Aisle, opposite the pulpit. A semicircular Sanctuary in memory of Jeremy Taylor was designed by Thomas Drew F.R.S.A. during the ministry of the Rev Beresford Knox in 1870. The Organ Aisle and baptistry were added at this time, and the Church was made rectangular with the addition of the Harding Aisle in 1899. A careful inspection of the exterior stonework shows the extent of these additions quite clearly.

The Conacher Organ dates from 1871 when Conacher of Huddersfield first installed it. It remains in use to this day. For many years early in the twentieth century a fee of a few shillings was paid per annum to the man who operated the hand operated organ blower through a narrow door to the left.

The first window on the Tower Aisle wall and its inscribed marble tablet recall with great respect the townspeople who served and died in time of war. These are placed as a tribute to those who served in the First World War. (1914-1918). A fuller list of those who served is on an illustrated inscribed parchment inside the tower door.

The oak Communion Table with the Reredos immediately behind it were presented in 1951 as a memorial to those who died in the 2nd World War. The panelling to either side was completed in 1952. Before the days of Archbishop Laud in the 1600's Communion Tables were located in the centre of churches. Recently this tradition has been renewed in contemporary places of worship. The Table at Dromore was placed in the centre of the Sanctuary in 1999.