Good article about this exhibit at the National Gallery in London, with some interesting historical notes:
"The Black Death, with all its pestilential potency, arrived on the Italian peninsula in early 1348 and, within a few months, some towns and cities had lost almost all their inhabitants. In Venice and Pisa, at least three-quarters died. Florence was so devastated that, for a long time, the disease was known as "the plague of Florence". In Siena, it raged from April until October and, according to one chronicler, 80,000 people died in those seven months, among them the great painters Ambrogio and Pietro Lorenzetti. The corpses, swollen with buboes, were pitchforked into common graves "like layers of lasagne". Work on Siena's cathedral - intended to rival the duomo of Florence in magnificence - was halted. Its truncated transept still stands as witness to the plague's abrupt intrusion into human plans. So do the many chronicles that end suddenly at this time, as their authors succumbed to the deadly miasma. Giovanni Villani wrote "and this pestilence lasted until -", but he died before he could fill in the blank. The present, as well as the future, seemed literally to be vanishing."