The Italian plague of 1629–1631, also referred to as the Great Plague of Milan, was part of the second plague pandemic that began with the Black Death in 1348 and ended in the 18th century. One of two major outbreaks in Italy during the 17th century, it affected northern and central Italy and resulted in at least 280,000 deaths, with some estimating fatalities as high as one million, or about 35% of the population. The plague may have contributed to the decline of Italy's economy relative to those of other Western European countries.
Thought to have originated in Northern France in 1623, the plague was carried throughout Europe as a result of troop movements associated with the Thirty Years' War and was allegedly brought to Lombardy in 1629 by soldiers involved in the War of the Mantuan Succession. The disease first spread to Venetian troops and in October 1629 reached Milan, Lombardy's major commercial centre. Although the city instituted a quarantine and limited access to external visitors and trade goods, it failed to eliminate the disease. A major outbreak in March 1630 resulted from relaxed health measures during the carnival season, followed by a second wave in the spring and summer of 1631. Overall, Milan suffered approximately 60,000 fatalities out of a total population of 130,000.
East of Lombardy, the Republic of Venice was infected in 1630–31. The city of Venice was severely hit, with recorded casualties of 46,000 out of a population of 140,000. Some historians believe that the drastic loss of life, and its impact on commerce, ultimately resulted in the downfall of Venice as a major commercial and political power.
Population before the plague and death toll, selected cities:
| City | Population in 1630 | Death estimates by 1631 | Percentage of population lost | |
|---|---|---|---|---|
| 54,000 | 33,000 | 61% | ||
| Parma | 30,000 | 15,000 | 50% | |
| Milan | 130,000 | 60,000 | 46% | |
| Venice | 140,000 | 46,000 | 33% | |
| Bologna | 62,000 | 15,000 | 24% | |
| Florence | 76,000 | 9,000 | 12% |