According to scholars at the University of Paris, the Black Death is created on March 20, 1345, from what they call “a triple conjunction of Saturn, Jupiter and Mars in the 40th degree of Aquarius, occurring on the 20th of March 1345″. The Black Death, also known as the Plague, swept across Europe, the Middle East and Asia during the 14th century, leaving an estimated 25 million dead in its wake.

READ MORE: Pandemics That Changed History: Timeline

Despite what these 14th-century scholars claimed the most common ailment known as the Black Death is caused by the yersinia pestis bacterium. The plague was carried by fleas that usually traveled on rats, but jumped off to other mammals when the rat died. It most likely first appeared in humans in Mongolia around 1320—although recent research suggests it may have existed thousands of years earlier in Europe. Usually, people who came down with the plague first complained of headaches, fever and chills. Their tongues often appeared a whitish color before there was severe swelling of the lymph nodes. Finally, black and purple spots appeared on the skin of the afflicted; death could follow within a week. Later, a pneumonic form of the plague developed that was less common but killed 95 percent of the people who contracted it.

After the nomadic tribes of Mongolia were devastated by the plague, it moved south and east to China and India. Wherever it went, the death toll was high. It is thought that the disease made its way to Europe in 1346. In one famous incident, the Tatars, a group of Turks, were battling Italians from Genoa in the Middle East when the Tatars were suddenly stuck down by the plague. Reportedly, they began catapulting dead bodies over the Genoans’ walls toward their enemy, who fled back to Italy with the disease. Although this account may not be true, it is certain that rats carrying the plague hitched rides on ships from Asia and the Middle East to Europe. In port cities everywhere, the Black Death began to strike. In Venice, 100,000 people died in total, with as many as 600 dying every day at the peak of the outbreak.

READ MORE: Rats Didn't Spread the Black Death—It Was Humans

In 1347, the disease worked its way to France and Paris lost an estimated 50,000 people. The following year, Britain fell victim. Typically, countries would believe themselves to be superior and immune to infection when their neighbors came down with the plague, but soon found they were mistaken as the Black Death traveled across Eurasia, spreading devastation in its wake. By the time the worst was over in 1352, one third of the continent’s population was dead.

Devastation on this scale brought out the worst in people. Often, it was not the movement of stars that was blamed for the disease, but the minorities in the community. Witches and gypsies were frequent targets. Jewish people were tortured and burned to death by the thousands for supposedly causing the Black Death. Preachers claimed that the disease was God’s punishment for immorality. Many turned to prayer and those that did survive ascribed their good luck to their devotion, resulting in the rise of splinter religions and cults in the aftermath of the plague’s destruction. Alternatively, some resorted to useless home cures to try to avoid the disease, bathing in urine or menstrual blood in an attempt to deter it.

The plague popped up periodically until the 1700s, but never again reached epidemic proportions after the 14th century.

READ MORE: How 5 of History's Worst Pandemics Finally Ended