The Horse Plague, as it came to be known, spread rapidly from Istanbul to the many ports of Europe. It got its name from the grotesque facial swelling that was commonplace among the victims. The buboes, unlike those caused by the Black Death, tended to be concentrated on the head and necks of the victims, which was said to give them a horselike appearance. Today, the Horse Plague is regarded by most historians to have been a mutation of the Bubonic Plague.
The Horse Plague, in terms of absolute numbers, was not nearly as destructive as the Black Plague that had preceded it. Though it spread over most of Europe, huge spaces in Eastern and Central Europe were spared. In other areas, the plague only infected large cities, leaving the people of the countryside relatively untouched.
Close to two thirds of the plague’s victims were concentrated in three regions. Western Anatolia, Italy, and the Iberian Peninsula were, for one reason or another, the most affected areas that the plague spread to. In Turkey, where the disease spread from, the great city of Istanbul experienced losses as high as 70% of the population. Other major cities of Western Anatolia experienced similar losses. These losses crippled the Ottoman Empire for a generation and would, in the years after the plague, create a population movement from the countryside to the vacated cities and from the Turkish lands in the Balkans to the depopulated cities of Anatolia.
In Italy, the Horse Plague was again concentrated in the cities, where the fleas that bore the illness could easily spread. The great trading city of Venice was the first to be infected, due to its constant contact with trading ships from Istanbul and elsewhere. After Venice, the islands of Sicily, Sardinia, and Corsica were infected, and from there the rest of Italy. Almost two centuries earlier, Milan and managed to escape the worst of the Black Death, but this time its people were not so lucky. With the depopulation of Italy’s major cities, a power vacuum developed, one that France and Austria would compete to fill in the coming years.
If the plague crippled one Empire in the Eastern Mediterranean, it found two to destroy in the West. The empires of Spain and Portugal, newly emerged from their Reconquista, were just stretching their legs as great Powers when the plague struck. Sevilla, Lisbon, and Madrid were the most affected, but all of the cities of the peninsula suffered. The destruction the plague wrought on Spain and Portugal diverted focus from their incipient empires and severely reduced their means to fund such ventures. Historians have called the Horse Plague the chief reason for the failure of Iberian colonialism in the Age of Discovery.