A mass grave of over 200 medieval bodies was recently discovered underneath a supermarket in Paris, Live Science reported.

Workers doing renovations at the Monoprix Réaumur-Sébastopol supermarket, in the city's second-arrondissement, were lowering the basement's floor level when they discovered the skeletons of hundreds of men, women and children buried neatly in rows from head to feet.

The bodies, possibly dating back to the 1300s, were divided into pits along the supermarket's foundation, which is the site of a medieval cemetery opened by the former Trinity Hospital. Most contained between five and 20 bodies while one pit alone contained over 150, according to a French statement on the discovery obtained by Live Science.

Researchers found no obvious signs of disease or anything else that might have caused their deaths. But the way they were buried- all together in one grave- suggests they died when there was widespread disease and there were too many fatalities to give each one a proper burial, experts said in the statement.

One possibility is the Black Death, which wreaked havoc upon Europe at its peak in 1353- the same year Trinity Hospital opened the cemetery at the site, according to a French Society presentation on the History of Medicine.

At the time another ancient Paris hospital, Hôtel-Dieu de Paris, saw hundreds of people dying every day. So officials at Trinity took on the extra bodies and charged for burials when there was no space left in the city.

Archaeologists are to use radiocarbon dating to determine when and how the individuals died.