Throughout the building of St.Paul’s, Wren discussed technical challenges with his trusted friend Robert Hooke who visited the site regularly to consult on engineering matters. Almost certainly Hooke was involved in the calculations for the design and construction of the dome even though it was probably not finalised until about a year after his death in 1703. Wren and Hooke had been researching loads and the properties of different types of stone for some years. Wren gave a demonstration of the distribution of load at the Royal Society in 1670 and Hooke followed that up with experiments, producing calculations and a representation of a dome a year later. As well as a mathematician, Wren was also an astronomer, so he determined the height of the dome at three hundred and sixty-five feet as a reminder of the number of days it takes the earth to circle the sun.
One of Wren’s challenges was to create and fix a light but durable outer skin for the dome. Lead was his chosen material but the problem was how to fasten it so that the fixings and the lead itself would not rust, rot or spoil over time. He devised a method of placing a wooden structure with the lead held in place using a system of ribs.
Wren realised that the dome would look tall and misshapen from the inside so his solution was to create a second, inner dome with an unseen sixty feet high space between the inner and outer domes. At one hundred and eight metres high and a diameter of over thirty five metres, the outer dome is the world’s second largest after St.Peter’s in Rome. St.Paul’s could (until recently) be seen from as far west as Windsor and the Thames Estuary in the east, although only on a clear day when rain had washed away London’s normal foggy haze.
Wren’s original plan was for the inside of the dome to be decorated in mosaic, but the Church Commissioners had other ideas and in 1709 appointed the artist James Thornhill. He created several designs in monochrome based on the life of St.Paul, which he tested by hanging them onto the dome before deciding the final version. Thornhill completed the painting in 1719.
The entire building is on a slightly different alignment to the one it replaced and thus it was not possible to incorporate Inigo Jones’s west portico that had been added a mere forty years earlier. It was demolished and its stones used for the foundations of the new building. Wren’s main entranceway facing Ludgate Hill was built between 1706 and 1708. It consists of two tiers of columns, topped by a pediment, with carvings showing the conversion of St.Paul. Each tower was designed to have clocks but the one on the left has always remained empty. The bell tower contains two bells. ‘Great Tom’ chimes the hours and ‘Great Paul’ strikes one o’clock each afternoon. It is older than the cathedral and is the largest swinging bell in Europe.
In 1708 the main part of the building work was complete and the last stone on the lantern laid at a ceremony attended by Wren, the master-mason Edward Strong, and other masons who had been involved in the construction. By then Wren was sixty-nine and had employed Strong on many of his projects over the decades. He had been joined by his son, Edward Strong Jnr., who had carried out the work of constructing the lantern, the last stone of which was put in place by Wren’s son, Christopher Jnr.
Some of the final minor works were taken out of the Wren’s hands, for which he complained bitterly to Queen Anne, and some of his ideas for mosaics and the interior of the dome never reached fruition. Statues on the roofline were not added until 1722. Wren particularly disliked the railings around the northern perimeter of the churchyard but they are today highly valued as one of the country’s earliest surviving examples of cast ironwork. Nevertheless, he continued to visit St.Paul’s, sitting under the dome to contemplate until his death at the age of ninety-one in 1723. He was buried in the crypt, with a simple plaque in Latin that states: “If you seek his monument, look around you”.
Five hundred and sixty tons of chalk, five hundred tons of rubble, fifty thousand tons of Portland stone, twenty-five thousand tons of other types of stone and eleven thousand tons of ragstone were used in the construction, as well as large quantities of marble, timber, sand, copper, lead and iron. More than seventy huge limestone blocks from the previous portico by Inigo Jones were incorporated into the foundations and bricks supplied in the 1690s were from the factory at Tilbury owned by Daniel Foe (who later found fame as the novelist Daniel Defoe). The woodcarvings of the Quire are by Grinling Gibbons and their wrought-iron gates by the French master metalworker Jean Tijou.
The first stone had been laid in June 1675. It had been the first time an English cathedral had been completed as the vision of one person during his lifetime. It was also the first in the English classical and baroque style and the only English cathedral to have a dome.
As he was working on site in the early 1670s, at the very beginning of the construction, Wren asked a workman to bring him a flat stone to use as a marker for the masons. He was given a fragment of a gravestone containing the single word RESURGAM (I will rise again) in large capitals, from Matthew 27:63. Wren decided to place a large phoenix above the south transept hovering over the word as a sign of London rising from the ashes of the Great Fire. The carving of the work was by the Danish artist Caius Gabriel Cibber who was also responsible for the relief at the base of the Monument.
Sources include: Various ‘St.Paul’s – The Cathedral Church of London’; Adrian Tinniswood ‘By Permission of Heaven’; Lisa Jardine ‘On A Grander Scale’; Peter Whitfield ‘London – A Life In Maps’; John Schofield ‘London 1100-1600’; Count Magalotti ‘Travels of Cosmo III’. Illustration courtesy of the collection of Hawk Norton.