From 1600 to 1700 London’s population trebled, from 200,000 to 585,000, outstripping the supply of what was then almost universally held to be an essential element of the city’s infrastructure, enough churches to accommodate worshippers and would-be worshippers, in particular, those of the Established Church of England.

Population estimate of Inner London (Former London County). Figures from http://demographia.com/dm-lon31.htm which in turn obtained pre-1801 data from The London Encyclopedia, Edited by Ben Weinreb and Christopher Hibbert
Early in the next century, in March 1711, the House of Commons considered a report on the estimated population of the London suburbs and the churches available for worship. In the most populous parishes, there was a total of just forty-six churches and chapels for a population of over half a million. It was estimated that only one person in three could find a place in the pews of the Church of England.
On 1 May 1711 the House of Commons resolved “That a Supply be granted to her Majesty for the Build of fifty new Churches, and for purchasing Sites of Churches and Church-Yards, or Burial-Places, and also Houses for the Habitations of the Ministers of the said Churches, in or about the Cities of London and Westminster, or the Suburbs thereof, and for making such Chapels as are already built and capable thereof, Parish-Churches; and also for finishing the Repairs of the Collegiate-Church of St. Peter’s Westminster, and the Chapels of the same.” This was followed up by legislation in 1712 “An Act for granting to her Majesty several Duties upon Coals, for building fifty new Churches, &c.” A Commission was established to oversee the building of the churches.
Building fifty new churches would ease the pressure for places where members of the Church of England could gather to worship and, it was hoped, potential Dissenters would have a reduced incentive to separate from the Established Church. (My Plaisted forebears became Dissenters about this time.)
The Commission did not achieve its target. Only twelve new churches were built, and just five existing churches were rebuilt.
One of the new churches was St George’s Hanover Square. The architect was John James, a pupil of Sir Christopher Wren. James’s neoclassical design, with a portico of six Corinthian columns, set a new trend in English church architecture.
Its location in Mayfair made St George’s Hanover Square the venue for many fashionable weddings. The first entry in the Marriage Register is dated April 30th, 1725. The most weddings in a single year was 1063, in 1816.
On 20 March 1813 my 4th great grandparents Charles Fox Champion Crespigny and Eliza Julia Trent married at St George’s Hanover Square. Charles Fox was twenty-seven. Eliza was a minor of sixteen, and her mother’s consent had to be provided. Charles’s half-brother Philip C Crespigny and Eliza’s brother John Trent were witnesses.

Bishop’s transcript of the marriage of Charles Fox Champion Crespigny and Eliza Julia Trent 20 March 1813 at St George’s Hanover Square. Image retrieved from ancestry.com London, England, Church of England Marriages and Banns, 1754-1932

Crespigny Trent marriage announcement in The Suffolk Chronicle; or Weekly General Advertiser & County Express. 8 May 1813 page 4. Retrieved from FindMyPast.
In 1813 weddings were not reported in the newspapers. However, in 1903 when Valerie Champion de Crespigny married Captain John Smiley at St George’s Hanover Square, her dress and the dresses of her six bridesmaids were described in detail.

The 26 November 1903 wedding of Captain John Smiley and Valerie Champion de Crespigny from The Queen 5 December 1903 page 58 retrieved from FindMyPast
In 1917 when Rose Champion de Crespigny née Gordon, a widow, remarried at St George’s Hanover Square, her photo appeared in The Tatler and a wedding photo appeared in a newspaper.
Rose Champion de Crespigny marries William Morrice. Newspaper clipping was being sold on EBay 2020, no other details available.
Ms William Morrice from The Tatler 21 November 1917 retrieved from FindMyPast
The composer George Handel (1685 – 1759) was a parishioner of St George’s from the time it was first built. He was consulted on the organ installation.
It is said that St George’s has changed little since it was first built and that “a parishioner from two centuries ago, if he could return today, would not find much to startle or dismay him.”

St George’s Hanover Square Church is shown with a black cross to the west of the City of London
Sources