The Collegiate Church of St Peter stands at the highest point of Wolverhampton, on a site hallowed by the prayers of Christian people for over one thousand years. It is a living monument to Wolverhampton’s long history, and it is a place where people come for special services, for joyful and solemn civic occasions, for concerts and recitals, for quiet in the middle of their busy lives as well as week by week to express their commitment to Christ and His Gospel.
The first church to be built on this site was the monastery of St Mary, which Lady Wulfrun rebuilt in 994. Her statue stands in the square outside. She endowed it with vast lands in Wolverhampton, Bilston, Willenhall, Wednesfield and Pelsall. She made it a Collegiate church and placed it in the care of a dean and seven prebendaries. Work on the present building started in 1425 and, of the earlier building, only the lower part on the outside walls, the base of the tower and the lower half of the porch remain. The church you see today is much as the mediaeval builders left it at the beginning of the 16th century, with the exception of the chancel which was completely rebuilt in 1867.
In 1479 King Edward IV united the Deanery of Wolverhampton with the Deanery of Windsor where he had recently built the chapel of St. George and he appointed Richard Beauchamp, Bishop of Salisbury, as the first Dean of Windsor and Wolverhampton. Other Deans include: Samson (chaplain to William the Conqueror and compiler of the Domesday Book); Peter of Blois (secretary to Henry II and Eleanor of Aquitaine); Christopher Urswick (who appears in Shakespeare’s Richard III, Act iv, Scene 5); Cardinal Bainbridge (who was poisoned in Rome); Owen Oglethorpe (who crowned Elizabeth I); and Matthew and Christopher Wren (uncle and father of the architect).
The union between the two survived throughout the Reformation, and Wolverhampton was the only Royal Peculiar in Staffordshire to be restored to that status after the accession of Queen Mary I in 1553. After the death of Dean Hobart in 1846, Parliament abolished the Deanery of Wolverhampton and St Peter’s became a Rectory in the Diocese of Lichfield.
For more information, this Wikipedia page is very informative.