FLORENCE — When the new disease first arrived, little was clear beyond the fact that it killed with terrifying speed. Near-certain death trailed the first symptoms by four days or less. The doctors were helpless. This city was soon overwhelmed with corpses. Workers in church yards dug pits down to the water table, layering bodies and dirt, more bodies and dirt.

One writer of the time compared the mass graves to “lasagna.”

Seven centuries later, the plague in Europe stands as an example of a pandemic at its worst — what happens when so many people die so quickly that some foresee the end of the human race. Few places were hit harder than Florence, whose population in 1348 was cut by at least one-third and possibly far more.

We had figured a trip to Florence might provide some comforting perspective on modern times — a chance to dwell on a period that was patently deadlier and more fear-inducing than the coronavirus pandemic. But instead, as we spoke with historians and searched for the plague’s lasting marks, what stood out most were the similarities, 672 years apart.

Theirs was a mysterious bacteria spreading at a time when people didn’t yet understand disease transmission; ours a novel virus infiltrating a world that prides itself on its medical knowledge. But in both cases, the first instinct was to close borders to try to keep the disease at bay. When that didn’t work, officials called for strict rules — but only some people paid attention. All the while, there was a proliferation of conspiracy theories. Many tried to blame the disease on outsiders or minorities — in medieval Europe, often Jews.

“Much has changed since the 1340s,” author John Kelly wrote in his book on the plague, “but not human nature.”