THE PARISH CHURCH OF ST GILES, WREXHAM is one of the finest examples of ecclesiastical architecture to be found in Wales. The main body of the church was built at the end of the 15th and beginning of the 16th centuries, spanning the final years of the medieval period and the opening decades of the modern age.

There may well have been a church in Wrexham as far back as the 11th century and the present church is probably the third to have been built on the site. Local legend has it that work on building a church was originally commenced on what is now Brynyffynnon but that each day's work was destroyed during the night. A watch was kept one night and, as the day's work collapsed, a voice was heard crying 'Bryn-y-grog' (the Hill of the Cross) and it was taken as a divine indication that the church should be built a few hundred yards away on the hill of that name.
Wrexham historian, A.N. Palmer, stated that the earliest reference which he was able to find to a church in Wrexham was 1220 when Reyner, the bishop of St Asaph, gave the  monks of Valle Crucis in Llangollen 'half of the [income of the] Church' of the town of Wrexham (the other half being given to them seven years later by the next bishop, Abraham). In reality what this meant was that the rectorial tithe income from the church was given to Valle Crucis. In 1247, Madog ap Gruffydd, Prince of Powys, bestowed upon the monks of Valle Crucis the patronage of the church of Wrexham which meant that the abbey also received the vicar's tithes.
On 25 November, 1330, the church tower (often referred to as a steeple) was blown
down, the result of which was that the whole church was rebuilt in the Decorated style. Some features of this 14th century church have survived and formed the basis of the outline of the nave and aisles of the 15th century building. Many believed that this catastrophe had befallen the tower because the market was being held on a Sunday. Consequently, market day was moved to a Thursday. The church is dedicated to St Giles although there is a strong local belief that it was once dedicated to the Celtic saint Silyn.
This may, however, have been an error of translation in that both Silyn and Giles can be translated into Latin as Aegidius. It may also be an indication that the origin of the church dates back to the time when Welsh churches were dedicated to Celtic saints, many of whom (Silyn included) were not recognised by the Roman Catholic church. Many churches in the Marches therefore adopted the name of a more legitimate patron. Certainly, by 1494 the church was known as 'the church of Saint Giles'.