“If only it would end!” wrote Galen of the so-called Antonine Plague, a pandemic that erupted during the reign of Marcus Aurelius. When the illness first arrived around 165 CE, Galen was already extremely experienced at treating a wide variety of ailments, and he had seen infectious diseases before—as a student in Pergamon, in 152 CE, he described a grisly epidemic that attacked the skin and flesh of patients—but this time the situation was much worse. The severity and duration of the Antonine Plague was different from what he had witnessed in the past. Throughout his writings, Galen generally expressed himself in a clear-eyed, rational, and confident style. But when describing his encounter with this epidemic, Galen departed from his typical clinical detachment:
Galen first personally encountered the plague during his trip to Aquileia in northern Italy, and the disease was already spreading throughout the Roman Empire. Likely picked up by the military during the war with the Parthian Empire in the east a few years earlier, the plague was then carried back west by the army following their victory. Galen described it as “the very long plague”: it continued to return in a series of outbreaks in the decades after its initial establishment in the mid-160s, and ancient sources suggest that the disease returned again in a large second wave in 189 CE. The pandemic moved more swiftly through some places than others—Rome was an epicenter—while certain locales managed to escape infection. The magnitude of the loss was enormous: an estimated fifteen million people died, as much as twenty-five percent of the Empire’s population.
References to “plagues” and “pestilence” are frequent in writings from the ancient world. Homer’s Iliad begins with a description of a plague as a sign of divine displeasure.
The historian Thucydides (ca. 460 BCE–ca. 400 BCE) writes about the Plague of Athens, which struck around 430 BCE, lasting a few years and killing an estimated 25 percent of the city-state’s population.
A different epidemic in Rome, in 293 BCE, led to the introduction of the cult of Asclepius as a civic measure to control the disease.
Livy (ca. 59 BCE–17 CE) and Ovid (43 BCE–ca. 17 CE) recount the tale: After consulting the oracular Sibylline Books, the Romans learned that the only way to stop the epidemic was by bringing the healing god Asclepius to their city from Epidaurus in Greece, the site of the famous Asclepius shrine. The Senate deployed a ship on a formal embassy, Asclepius consented, and the god journeyed to Rome in the form of a giant snake. As the ship sailed up the Tiber, the serpent-god jumped out of the boat and swam ashore for an island in the river, known today as Tiber Island. Since the god had selected this island as his home, an Asclepieion was constructed there. Thus ended the plague. (Tiber Island has remained a destination for healing even to the present day; where the Asclepieion temple once stood, there is now a hospital.)
When the Antonine Plague arrived centuries later, the response from many towns was similar, and delegations were sent to consult oracles for divine instructions on how to limit sickness and death. Shrines attracted supplicants and statues to Apollo and other gods were erected. Although many writings about the episode have been lost, extant texts offer insight into the response. Aelius Aristides, Galen’s acquaintance with a “strong soul and a weak body,” writes in Sacred Tales of his own bout with the plague, his personal devastation as family and friends succumbed, as well as its horrific effects on the city of Smyrna. Aristides, too, believes he was saved from death by following a diet prescribed by Asclepius in a dream.
Although we have a few written accounts of the Antonine Plague, only Galen described the disease in detailed clinical terms. He carefully documented symptoms of epidemic victims: a black, ulcerative-then-scabbing full-body rash; ulcerations of the larynx, trachea, and esophagus; black diarrhea; coughing; intense heat; pulse changes; and possibly disfiguring scarring. Galen was working in an era before germ theory, and he makes only one passing speculative comment about the plague’s possible transmission, noting the Hippocratic concept that breath could “corrupt” the air. Although it is difficult to diagnose illnesses retroactively based on ancient descriptions—in part because Galen understood the plague in humoral terms as an accumulation of black bile, and in part because infectious diseases themselves mutate and change over time—historians today believe that the Antonine Plague could have been a visitation of smallpox, but it remains an ongoing point of scholarly debate.
Galen treated hundreds of patients before distancing himself from its epicenter not long after the outbreak. Smallpox is extremely contagious, and Galen never mentions becoming ill with the plague himself. If the disease was indeed smallpox, how did he avoid contracting it and how did he treat it? It is possible that an ancient strain of smallpox may have allowed for asymptomatic carriers; or, following years of animal dissections and vivisection, Galen may have developed immunity from a less-severe animal-infecting relative of the virus (cowpox, for example, can provide protection against smallpox). Galen describes a number of different treatments for the plague—milk from Stabiae (near Pompeii), earth from Armina, urine of a boy—and while he considers some of these prescriptions helpful, even his otherwise heroic powers were limited in the face of the pandemic: