When fire shot through the City of London over the course of three days in early September 1666, razing everything in its path, the future of England’s capital – its very existence – was in jeopardy. Although the estimated death toll remained remarkably low for a fire that wreaked such destruction, the City itself looked much different when the final smouldering was extinguished.More than 13,000 houses had been destroyed, along with nearly 90 churches. Some significant buildings were lost to the flames, including the original St Paul’s Cathedral and the Royal Exchange, as well as the city gates at Aldersgate, Ludgate and Newgate. The subsequent history of England would have taken a different complexion had its entire capital been lost. As it was, the flames were largely limited to the City of London.A few historians have even suggested that, in some regards, the Great Fire of London turned out to be a force for good. The principal tenet of this line of thinking revolves around the Great Plague. The belief is that, when fire broke out, the epidemic – which had ripped so easily through the cheek-by-jowl living quarters of the City the previous year – would have found it much harder be transmitted; in short, that the fire killed off the epidemic, certainly in London.Did you know?Thomas Farriner’s bakehouse (where the Great Fire of London began) was not located on Pudding Lane, as traditionally believed. Hearth tax records show it was actually sited on Fish Yard, a small enclave off Pudding Lane.Dr Clare Jackson – senior tutor at Trinity Hall, Cambridge and author of the award-winning Devil-Land: England Under Siege, 1588–1688 (Allen Lane, 2021) – dismisses this theory. “This is a myth. The Great Fire had not spread to areas that had experienced particularly high levels of plague infection, such as Southwark, Clerkenwell and Whitechapel.” That is, the flames failed to reach certain districts, so couldn’t have had an impact on plague numbers.Plus, the timeline of the epidemic doesn’t neatly tally with the timeline of the Great Fire, as Dr Jackson explains: “Plague mortality had already started to decline from late 1665, while people also continued to die from plague after the Fire. Popular associations between the Great Plague of 1665 and the Fire of 1666 arise only from their close chronological proximity.”On the podcast | Rebecca Rideal responds to listener questions about the devastating blaze that swept through the capital in 1666:Understandably, the Great Fire caused mass migration from the City of London to surrounding areas. But this alone didn’t reshape the city, especially as much of this migration was only short term as the homeless sought temporary shelter in the open land beyond the city limits, particularly to the north. By then, London was already swiftly expanding and swelling.More like this“Before the Fire, there had already been significant expansion westwards, with local populations moving beyond the City’s walls to escape overcrowding. Newly fashionable areas such as St James, Covent Garden and Westminster were attracting the gentry and upwardly mobile migrants, while poorer families were tending to move eastwards.”A speedy recoveryRather than licking its wounds, the City of London swiftly set about rebuilding itself. The economy obviously took an immediate knock, but it wasn’t as catastrophic a hit as might have been expected. “While there was inevitable short-term disruption to trade,” explains Dr Jackson, “the speed with which the authorities embarked on rapid rebuilding and recovery was remarkable. Two sets of plans for the City’s rebuilding had already been submitted to the government of Charles II by 13 September 1666, only a week after the Fire ended. By 1670, around 6,000 houses had been rebuilt.”One legacy of the Great Fire was the use of less flammable materials in building; the Rebuilding Act of 1667 specified that “all the outsides of all buildings in and about the said City be henceforth made of brick or stone”.However, as Dr Jackson clarifies, the events of 1666 can’t take complete credit, pointing out that, during the early 1600s, James VI and I had made similar restrictions on the use of materials in construction in London, “both to reduce fire risk and to reserve timber for England’s Navy ships. Such orders had, however, often been disregarded, but the Fire of 1666 provided an opportunity for widespread enforcement, as City authorities were given the right to demolish illegally built houses.”In context: the Great Fire of LondonFrom Sunday 2 to Wednesday 5 September 1666, the City of London was overwhelmed by the largest, fastest-moving fire it had ever experienced, one that razed most of the buildings within its walls to the ground. Having broken out in a bakery just after 12am, the fire spread swiftly through the night.There was a chance to contain its reach early on by demolishing buildings ahead of its path to create firebreaks, but the Lord Mayor dallied over authorising such measures and the fire took serious hold. Fanned by easterly winds, it roared largely unchallenged across the entire City.The flames only dissipated when the wind dropped nearly 72 hours after its outbreak. It was “the saddest sight of desolation that I ever saw,” recorded the famed diarist Samuel Pepys.One of the grandest rebuilds was, of course, the magnificent Sir Christopher Wren-designed St Paul’s Cathedral, which still dominates the London skyline as viewed looking northwards from the South Bank of the Thames. That’s an undisputed visual reminder of the Fire.One last potential legacy of 1666 concerns how prepared London was for subsequent outbreaks of fires. Within a few years, the large-scale adoption of fire insurance became standard practice, but the idea that a new emergency service was immediately created is again debunked by Dr Jackson. “There were a few new fire pumps, but the first city-wide fire service was not created until January 1833.”Perhaps it should have come into force earlier. In 1676, 600 houses in Southwark were lost to a blaze, and a further 1,000 in Wapping six years after that. In conclusion, although it accelerated certain developments that were already afoot, had the Great Fire not happened, the course of English history wouldn’t have been terribly affected. However, if the wind hadn’t dropped three days into the fire and the flames had continued to consume all before them, the events of September 1666 could have left the country without a capital city.Clare Jackson is senior tutor of Trinity Hall at the University of Cambridge. She has presented the BBC2 series The Stuarts and its sequel, The Stuarts in Exile, and is author of Devil-Land: England under Siege 1588-1688 (Allen Lane, 2021)This article was first published in the October 2022 edition of BBC History Revealed