According to local tradition in AD 635 St Birinus, the first person to bring Christianity to the area, baptised Cyngils, King of the West Saxons, in the spring just west of the church.
Toward the end of the 19th century, it became apparent that the first chapel was inadequate in many respects and, as there was no way of enlarging it, a new site and building had to be found. It was decided that the ground behind Old College was to be the site of the new chapel. The original chapel was designed in 1879 by the Royal Engineers in a style copied from a church in Florence. It is constructed mainly in red brick, with terracotta moulding, large interlocking pediment copies and massive corbels.
The second chapel to be built is actually contained within the third, present and most recent structure, though the latter was cleverly positioned, at right angles, around the existing chapel of Christ Church. This second edifice was named Christ Church and many of the features of that building, a narrow rectangular shaped structure, can be clearly seen around the present building.
After the Great War the Royal Military College Chapel of Christ Church became the Royal Military Memorial Chapel and in 1919 plans by architect Captain Arthur C Martin were agreed for an enlarged building. Martin, who designed the new building in a Byzantine style, changing the orientation of the chapel from South East to North East. It was duly consecrated by the Archbishop of Canterbury in 1921, although work continued on the new west end for a further 16 years. King George VI dedicated the new chapel on 2nd May 1937 on completion of the final phase of the building programme that transformed the building into the chapel we know today.