Located in the market place in the heart of the medieval city of Norwich, St Peter Mancroft is the largest of the city’s 31 surviving medieval parish churches and one of the finest perpendicular parish churches in Norfolk. It is known for its medieval stained glass, its collection of medieval and renaissance treasures and its importance as a pioneering tower in the uniquely English art of change-ringing on church bells.
Like the market place where St Peter Mancroft stands, the Church was a Norman foundation built by Ralph de Guader, Earl of Norfolk, in 1075. The Normans tried to suppress the old market, held in Tombland, by building their Cathedral and monastery enclosure over it and set up a new market place in the great field below the Castle where they could keep an eye on it.
Not long after, Earl Ralph lost everything in rebellion against William the Conqueror. Ralph had bestowed the church on one of his chaplains, Wala, who in turn passed it to the Abbey of St Peter in Gloucester where he fled after the Rebellion. For 300 years it was known as St Peter of Gloucester in Norwich. In 1388, after local pressure, it passed to the Benedictine community of St Mary-in-the-Fields whose Church stood on the site of the present day Assembly House and Theatre Royal.
The Dean and Chapter of St Mary’s found the old Church of St Peter in a poor condition and in 1390 they decided to rebuild it. However, it was not until 1430, with gifts and legacies from wealthy citizens, and donations from merchant and craft guilds, that the first stone was laid. The church was consecrated 25 years later. The present building owes much of its unity of style to a single phase of construction.
Was the original medieval stained glass kept and reused when the new church was built in the mid 15th century?
The medieval glass was mostly reconstructed into the East Window.
http://www.norfolkstainedglass.org/St_Peter_Mancroft/home.shtm