London had already burned several times in its history, most notably in 1212, but in September 1666 the conditions were present for an inferno of epic proportions. The city of 500,000 people was a tinderbox of cramped streets and timber-frame structures, many of them built with flammable pitch and tar. Stables filled with hay and straw were everywhere, and many cellars and warehouses were packed with combustible materials such as turpentine, lamp oil and coal. To make matters worse, a months-long drought had created a water shortage and left most of the wood buildings kindling dry.

The fateful spark in the Great Fire came early on Sunday, September 2, at the Pudding Lane bakery of Thomas Farriner. Before heading to bed that night, Farriner had made a final inspection of his bakery and raked the spent coals in his ovens, which were still warm from a day of making ship’s biscuit for King Charles II’s navy. He would later swear that the ovens were extinguished when he retired to his upstairs apartment, but it seems that a smoldering ember escaped and started a fire. Whatever the cause, at around 1 a.m., Farriner awoke to find his house in flames. The baker and his daughter only survived by exiting an upstairs window and crawling on a gutter to a neighbor’s house. His manservant also escaped, but another servant, a young woman, perished in the smoke and flames.

By the time Farriner joined the crowd gathering on Pudding Lane, the fire had already consumed most of his house. A few neighbors formed a bucket brigade and began throwing water on the flames, but most simply stood idle or rushed home to secure their valuables. Sir Thomas Bludworth, London’s Lord Mayor, took even less action. After arriving to inspect the blaze, he pronounced it so insignificant that “a woman might piss it out” and returned to bed.

Fanned by a powerful easterly wind, the bakery fire soon spread to other buildings on Pudding Lane before leaping to nearby Fish Street, where it torched the stables of a hotel called the Star Inn. When it reached a ship’s supply store, it heated up several barrels of tar, which exploded and rained flaming debris across the neighborhood. The blaze then moved south toward the River Thames, consuming every building in its path. The Church of St. Magnus the Martyr went up in smoke—one of the first of the 84 churches lost in the fire—as did dozens of riverside guildhalls and warehouses. Flames also ripped through half the buildings and waterwheels on London Bridge but were halted when they reached a gap in construction caused by a previous fire in 1633.

By sunrise, the inferno was burning out of control across the Thames waterfront. Samuel Pepys, a civil servant and diarist, wrote of panicked Londoners “staying in their houses as long as till the very fire touched them, and then running into boats, or clambering from one pair of stairs by the waterside to another.” Other people simply cast their furniture and other goods directly into the Thames. As the day wore on, the wind continued to feed the fire and blow it west across the homes, halls and churches of central London. Pepys described “a most horrid malicious bloody flame” that stretched for over a mile. “It made me weep to see it,” he wrote.

The Great Fire only grew more horrific on September 3. By then, the wind had carried sparks and embers across the city, starting scattered fires away from the main blaze. Fearing that the entire city would burn, King Charles II placed his brother James II, Duke of York, in charge of firefighting efforts. The Duke organized fire brigades that used heavy chains, ropes and grapples to pull down houses and create firebreaks to stop the inferno’s advance. Yet the blaze was moving so fast that it repeatedly overran the men as they worked. That evening, it roared through the Royal Exchange before engulfing Baynard’s Castle, a centuries-old fortress.

As the fire spread, so too did wild rumors about its cause. England was embroiled in the Second Anglo-Dutch War, and frantic Londoners soon began to speculate that the blaze was the result of arson by enemy agents or Catholic terrorists. Armed mobs eventually took to the streets and pounced on anyone with a foreign accent. One Frenchman had his house destroyed after the rabble became convinced he was planning to set it on fire. Elsewhere, a man was attacked when a mob mistook the box of tennis balls he was carrying for combustible “fireballs.”

While Londoners searched for a scapegoat, the flames continued their determined march across the city. On September 4, London’s Guildhall burned along with most of the structures on Cheapside, one of the city’s wealthiest streets. As the fire raged, many people took refuge in St. Paul’s Cathedral, a medieval church whose 500-foot spire had long dominated the London skyline. It was thought that St. Paul’s stone edifice and wide plazas would protect it, but at around 8 p.m., the inferno engulfed the church and sent its occupants fleeing for their lives. According to writer John Evelyn, the flames melted the church’s lead roof, sending molten metal “down the streets in a stream” that left “the very pavements glowing with a fiery redness.”

St. Paul’s would prove to be one of the last major buildings to fall victim to the Great Fire. That same night, the fierce easterly wind that had been feeding the blaze finally abated, allowing the Duke of York’s brigades to make progress with their firebreaks. On the other side of the city, the Tower of London’s garrison used gunpowder to demolish properties and halt the fire in its tracks. By the afternoon of September 5, the fires were corralled and starting to burn themselves out. Most were extinguished the following day.

All told, the Great Fire had destroyed 13,200 buildings and left an estimated 100,000 people homeless. Over 400 acres of the city had burned, leaving behind a desert of charred stone and smoldering wood beams. “London was, but is no more,” Evelyn lamented. Compared to the scale of the destruction, the supposed death toll was minuscule. Official reports listed as few as four people killed, but many modern researchers believe the number failed to include those whose bodies were cremated by the flames. “The true death toll of the Great Fire of London is not four or six or eight,” author Neil Hanson has argued, “it is several hundred and quite possibly several thousand times that number.”

While a Parliamentary investigation later blamed the fire on “the hand of God upon us, a great wind and the season so very dry,” many Londoners continued to believe it was the work of a foreign-born arsonist. At one point in the witch-hunt, a slow-witted Frenchman named Robert Hubert confessed to having firebombed Farriner’s bakery. Hubert was almost certainly innocent—he wasn’t even in London when the blaze began—but he was still hanged in October 1666. Despite all evidence to the contrary, rumors that the fire was part of a foreign or Catholic plot would persist for decades.

As it had been many times before, London was rebuilt following the Great Fire. Architects seized on the opportunity and presented ambitious building schemes, some of which called for boulevards and piazzas modeled after the great cities of France and Italy. In the end, however, the new London looked much the same as the old one, albeit with wider alleys and more brick structures. By far the biggest construction project was architect Christopher Wren’s new St. Paul’s Cathedral, which was completed in 1711, 45 years after the original burned in the Great Fire. The rebuilt cathedral would later become famous for surviving what has often been called the “Second Great Fire of London”—an incendiary bomb attack during World War II’s London Blitz.