The church of Christchurch Newgate stands on the site of the old Greyfriars Priory which was established in 1225 by the Franciscans. It was an important intellectual centre – of a similar status to Oxford University. William of Ockham – he of the famous “Ockham’s Razor” was a member. But in 1538 Henry VIII abolished the institution as part of the Dissolution of the Monasteries. The map below shows the extend of the precinct of the Priory superimposed on a map of London in 1900. The dark purple shows where the main church stood – in the same location as the ruins of the church today. The lighter purple shows the outbuildings and the pink represents the tenements and shops that the priory leased out to lay people for commercial purposes.
Henry VIII gave the property to the City of London and a new parish was formed combining together the old churches of St Nicholas Shambles and St Audoen ( sometimes spelt as Ewen) which stood nearby in Newgate with the old precinct of Greyfriars priory. This parish and the priory’s church were renamed Christchurch Newgate or sometimes Christchurch Greyfriars.
There is a blue plaque memorialising the Greyfriars priory in Newgate Street shown in the photo below that you can find in Newgate street.
Christchurch Newgate was destroyed in the Great Fire of London and rebuilt to Wren’s designs with the impressive steeple finally completed in 1704. The church of St Leonard Foster Lane which was also destroyed in the fire was not rebuilt and the parish was combined with Christchurch Newgate. Sadly, the church suffered extensive damage in the Blitz of 1940 and a decision was taken not to rebuild it but to leave the steeple and the ruins as a public garden. The parish was combined with St Sepulchre. Today you can still find some parish boundary markers in Newgate that show the old line between St Sepulchre and Christchurch Newgate as shown in the photos below:
The old churchyard of Christchurch Newgate was combined with St Leonards Foster Lane and St Botolph Aldersgate to create Postman’s Park and you can see a memorial plaque near the entrance in King Edward Street.
See here for the wikipedia page on Christchurch Newgate