Question: St Dionis Backchurch was rebuilt after a major conflagration that consumed how many parish churches?

Passages:
The Archdeaconry of St Andrews was a sub-division of the diocese of St Andrews, one of two archdeaconries within the diocese.  The St Andrews archdeaconry was headed by the Archdeacon of St Andrews, a subordinate of the Bishop of St Andrews.  In the medieval period, the Archdeaconry of St Andrews contained five deaneries with a total of 124 parish churches.  The deaneries were Mearns (14 churches), Angus (38 churches), Gowrie (20 churches), Fife (28 churches) and Fothriff (24 churches). St Dionis Backchurch was a parish church in the Langbourn ward of the City of London.  Of medieval origin, it was rebuilt after the Great Fire of London to the designs of Christopher Wren and demolished in 1878. The Great Fire of London was a major conflagration that swept through the central parts of the English city of London from Sunday, 2 September to Wednesday, 5 September 1666.  The fire gutted the medieval City of London inside the old Roman city wall.  It threatened but did not reach the aristocratic district of Westminster, Charles II's Palace of Whitehall, and most of the suburban slums.  It consumed 13,200 houses, 87 parish churches, St Paul's Cathedral, and most of the buildings of the City authorities.  It is estimated to have destroyed the homes of 70,000 of the City's 80,000 inhabitants. St Mary's Church is an active Anglican parish church located in Monk's Lane, Acton, a village to the west of Nantwich, Cheshire, England.  Since 1967 it has been designated a Grade I listed building.  A church has been present on this site since before the time of the Domesday Survey.  The tower is the oldest in Cheshire, although it had to be largely rebuilt after it fell in 1757.  One unusual feature of the interior of the church is that the old stone seating around its sides has been retained.  In the south aisle are some ancient carved stones dating back to the Norman era.  The architectural historian Alec Clifton-Taylor includes the church in his list of 'best' English parish churches.  In the churchyard is a tall 17th-century sundial.  The church is an active Anglican parish church in the diocese of Chester, the archdeaconry of Macclesfield and the deanery of Nantwich.  Its benefice is united with those of St David, Wettenhall, St Oswald, Worleston, and St Bartholomew, Church Minshull. Minster is an honorific title given to particular churches in England, most famously York Minster in York, Westminster in London and Southwell Minster in Southwell.  The term "minster" is first found in royal foundation charters of the 7th century.  Although it corresponds to the Latin "monasterium" or monastery, it then designated any settlement of clergy living a communal life and endowed by charter with the obligation of maintaining the daily office of prayer.  Widespread in 10th-century Anglo-Saxon England, minsters declined in importance with the systematic introduction of parishes and parish churches from the 11th century onwards.  It continued as a title of dignity in later medieval England, for instances where a cathedral, monastery, collegiate church or parish church had originated with an Anglo-Saxon foundation.  Eventually a minster came to refer more generally to "any large or important church, especially a collegiate or cathedral church".  In the 21st century, the Church of England has designated additional minsters by bestowing the status on existing parish churches. The Iron Church or The Cast Iron Church is a term which has been used to refer to any of the three churches built in Liverpool in the early 19th century by John Cragg, who ran the Mersey Iron Foundry.  The churches incorporated substantial cast iron elements into their structure and decoration.  Two of these churches are still in existence and are active Anglican parish churches.  These are St George's Church, Everton, and St Michael's Church, Aigburth.  The third church, now demolished, was St Philip's in Hardman Street. St Dionis Mission Hall is a Grade II listed church hall at 18a Parsons Green, London, SW6 4UH. Eighty-eight parish churches were burned during the Great Fire of London in 1666.  The office of Christopher Wren rebuilt 51 parish churches and St Paul's Cathedral.  Many of these churches were demolished as the population of the City of London declined in the 19th century and more were destroyed or damaged during the Blitz. Sir Thomas Graham Jackson, 1st Baronet {'1': ", '2': ", '3': ", '4': "} (21 December 1835 – 7 November 1924) was one of the most distinguished English architects of his generation.  He is best remembered for his work at Oxford for Oxford Military College as well as the University, notably: the Examination Schools, most of Hertford College (including the Bridge of Sighs over New College Lane), much of Brasenose College, a range at Trinity College, and the Acland Nursing Home in North Oxford.  Much of his career was devoted to the architecture of education and he worked extensively for various schools, notably Giggleswick and his own alma mater Brighton College.  Jackson designed the former town hall in Tipperary Town, Ireland.  He also worked on many parish churches and the college chapel at the University of Wales, Lampeter.  He is also famous for designing the chapel (amongst other things) at Radley College.  The City of Oxford High School in George Street, Oxford was another building designed by him. St Dionis Vicarage is a Grade II listed vicarage at 18 Parsons Green, London, SW6 4UH.  It was built in 1898-99 to a design by the architect William White.

Supporting sentences:
St Dionis Backchurch was a parish church in the Langbourn ward of the City of London.  Of medieval origin, it was rebuilt after the Great Fire of London to the designs of Christopher Wren and demolished in 1878. The Great Fire of London was a major conflagration that swept through the central parts of the English city of London from Sunday, 2 September to Wednesday, 5 September 1666.  It consumed 13,200 houses, 87 parish churches, St Paul's Cathedral, and most of the buildings of the City authorities.