Nearly 700 years after the Black Death swept through Europe, it still haunts the world as the worst-case scenario for an epidemic. Called the Great Mortality as it caused its devastation, this second great pandemic of Bubonic Plague became known as the Black Death in the late 17th Century.

Modern genetic analysis suggests that the Bubonic plague was caused by the bacterium Yersinia pestis or Y. pestis. Chief among its symptoms are painfully swollen lymph glands that form pus-filled boils called buboes. Sufferers also face fever, chills, headaches, shortness of breath, hemorrhaging, bloody sputum, vomiting and delirium, and if it goes untreated, a survival rate of 50 percent.

During the Black Death, three different forms of the plague manifested across Europe. Below is a timeline of its gruesome assault on humanity.

1346

The strain of Y. pestis emerges in Mongolia, according to John Kelly’s account in The Great Mortality. It is possibly passed to humans by a tarabagan, a type of marmot. The deadliest outbreak is in the Mongol capital of Sarai, which the Mongols carry west to the Black Sea area.

Mongol King Janiberg and his army are in the nearby city of Tana when a brawl erupts between Italian merchants and a group of Muslims. Following the death of one of the Muslims, the Italians flee by sea to the Genoese outpost of Caffa and Janiberg follow on land. Upon arrival at Caffa, Janiberg’s army lays siege for a year but they are stricken with an outbreak. As the army catapults the infected bodies of their dead over city walls, the under-siege Genoese become infected also.

May, 1347

Both sides in the siege are decimated and survivors in Caffa escape by sea, leaving behind streets covered with corpses being fed on by feral animals. One ship arrives in Constantinople, which, once infected, loses as much as 90 percent of its population.

October, 1347

Another Caffan ship docks in Sicily, the crew barely alive. Here the plague kills half the population and moves to Messina. Fleeing residents then spread it to mainland Italy, where one-third of the population is dead by the following summer.

November, 1347

The plague arrives in France, brought by another of the Caffa ships docking in Marseille. It spreads quickly through the country.

January, 1348

A different plague strain enters Europe through Genoa, brought by another Caffan ship that docks there. The Genoans attack the ship and drive it away, but they are still infected. Italy faces this second strain while already battling the previous one.

Y. pestis also heads east from Sicily into the Persian Empire and through Greece, Bulgaria, Romania and Poland, and south to Egypt, as well as Cyprus, which is also hit with destruction from an earthquake and deadly tidal wave at the same time.

Venice faces its own outbreak by pioneering the first organized response, with committees ordering ship inspections and burning those with contagions, shutting down taverns, and restricting wine from unknown sources. The canals fill with gondolas shouting official instructions for disposing of dead bodies. Despite those efforts, the plague kills 60 percent of the Venetian population.

April, 1348

The plague awakes an anti-Semitic rage around Europe, causing repeated massacres of Jewish communities, with the first one taking place in Provence, where 40 Jews were murdered.

June, 1348

The plague enters England through the port of Melcombe Regis, in Dorset. As it spreads through the town, some escape by fleeing inland, inadvertently spreading it further.

Summer, 1348

A group of religious zealots known as the Flagellants first begin to appear in Germany. These groups of anywhere from 50 to 500 hooded and half-naked men march, sing and thrash themselves with lashes until swollen and bloody. Originally the practice of 11th-century Italian monks during an epidemic, they spread out through Europe. Also known for their violent anti-Semitism, the Flagellants mysteriously disappear by 1350.

The plague hits Marseille, Paris and Normandy, and then the strain splits, with one strain moving onto the now-Belgian city of Tournai to the east and the other passing through Calais. and Avignon, where 50 percent of the population dies.

The plague also moves through Austria and Switzerland, where a fury of anti-Semitic massacres follow it along the Rhine after a rumor spreads that Jews had caused the plague by poisoning wells, as Jennifer Wright details in her book, Get Well Soon, History’s Worst Plagues and the Heroes Who Fought Them. In towns throughout Germany and France, Jewish communities are completely annihilated. In response, King Casimir III of Poland offers a safe haven to the persecuted Jews, starting a mass migration to Poland and Lithuania. Marseilles is also considered a safe haven for Jews.

October, 1348

Following the infection and death of King Edward III’s daughter Princess Joan, the plague reaches London, according to King Death: The Black Death and its Aftermath in Late-Medieval England by Colin Platt. As the devastation grows, Londoners flee to the countryside to find food. Edward blames the plague on garbage and human excrement piled up in London streets and in the Thames River.

February, 1349

One of the worst massacres of Jews during the Black Death takes place on Valentine’s Day in Strasbourg, with 2,000 Jewish people burned alive. In the spring, 3,000 Jews defend themselves in Mainz against Christians but are overcome and slaughtered.

April, 1349

The plague hits Wales, brought by people fleeing from Southern England, and eventually kills100,000 people there.

July, 1349

An English ship brings the Black Death to Norway when it runs aground in Bergen. The ship’s crew is dead by the end of the week and the pestilence travels to Denmark and Sweden, where the king believes fasting on a Friday and foregoing shoes on Sunday will please God and end the plague. It doesn’t work, killing two of the king’s brothers and moving into Russia and also eastern Greenland.

March, 1350

Scotland, having so far avoided the plague, hopes to take advantage of English weakness by amassing an army and planning an invasion. While waiting on the border to begin the attack, troops became infected, with 5,000 dying. Choosing to retreat, the soldiers bring the disease back to their families and a third of Scotland perishes.

1351

The plague’s spread significantly begins to peter out, possibly thanks to quarantine efforts, after causing the deaths of anywhere between 25 to 50 million people, and leading to the massacres of 210 Jewish communities. All total, Europe has lost about 50 percent of its population.

1353

With the Black Death considered safely behind them, the people of Europe face a changed society. The combination of the massive death rate and the numbers of survivors fleeing their homes sends entrenched social and economic systems spiraling. It becomes easier to get work for better wages and the average standard of living rises.

With the feudal system dying, the aristocracy tries to pass laws preventing any further rise by the peasants, leading to upheaval and revolution in England and France. Significant losses within older intellectual communities brought on an unprecedented opportunity for new ideas and art concepts to take hold, directly leading to the Renaissance and a more youthful, enlightened period of human history.

The Bubonic Plague never completely exits, resurfacing several times through the centuries.