The church may have been operating on its initial site from buildings that were part of a royal palace established in the 500s AD,[3] in the Kingdom of Powys, who had their capital at Shrewsbury, when it was known as Pengwern.

The distinctive round shape and high tower of the new building is a well-known landmark in the town, near the Quarry area of parkland.

Medieval Welsh literary evidence suggests that the bishops of Lichfield may have obtained possession of the endowments of a Celtic church at Shrewsbury.

The earliest piece of Welsh evidence for this is the Lament for Cynddylan incorporated in the poems of Llywarch Hen, which date in their written form to c. 850.

[14] Remains of the college of St Chad can be traced in the land adjoining the south-western extremity of the church on the old site, with portions of the wall traceable to a considerable distance in the neighbouring gardens.

[11] It is possible that, in Clive House, in the drawing room an alcove with an inset oak framework, remains of the buttery of St Chad's College survive in situ.

[15] There was a "Great Fire of Shrewsbury" in 1394 and the St Chad's Church building extant at that time was consumed in that event; the damage was so considerable that King Richard II remitted the town's taxes for three years towards the repairs.

[11] Henry VII visited Shrewsbury in 1490, and observed the feast of St. George in the collegiate church of St. Chad, along with his queen and Prince Arthur.

[17] In 1581, Sir Henry Sidney, celebrated the feast of St. George, in Old St Chads on April 23, with great splendour: a solemn procession went from the Council House to St. Chad's Church, the choir of which was fitted up in imitation of St. George's Chapel, Windsor, and the stalls decorated with the arms of the Knights of the Garter.

[18] It also had a peal of ten bells, and on the south was the church-yard, which owing to the " accumulated remains of successive generations, during more than eleven centuries, had been raised to the level of the window sills," making the Church damp.

[28] This having been decided, the committee's next task was to find a site for the new church, and Steuart was asked to provide a sketch of his design to help fix the location.

When the committee objected, he told them that he had assumed from their silence that they approved of the plan, and that he required to be paid for the work done before he would submit a new set of drawings.

By this time, the planning process had been so hampered by argument and delay that the committee thought it preferable to simply go ahead with the round design.

The entrance hall has many memorials relating to the 53rd Regiment of Foot, and its successor regiment the King's Shropshire Light Infantry (KSLI) including: In 1913, a vestry off the right hand side of the entrance lobby was converted to a chapel of St Aidan, in memory of former vicar Richard Eden St Aubyn Arkwright.