The First Recorded Bubonic Plague Pandemic in Europe That Killed Up to Half the Population of the Eastern Roman Empire Between 541 and 549 CE

The Eastern Roman empire under Justinian I was at its post-Roman territorial peak in 541 CE. The reconquest of Italy and North Africa was largely complete. The treasury was depleted by the wars but solvent. The reconstruction of the Hagia Sophia (completed 537) was the most prominent of a series of major imperial building projects.

In autumn 541 CE a previously unknown disease reached the Egyptian port of Pelusium at the eastern mouth of the Nile. It spread westward along the Mediterranean coast through winter 541-542 CE and reached Constantinople in spring 542 CE.

What Procopius described

The court historian Procopius of Caesarea — present in Constantinople during the outbreak — devoted Book II, chapters 22-23 of his History of the Wars to a clinical description of the disease. The description is the most detailed pre-modern account of a major epidemic in any surviving European source.

The symptoms were:

— Sudden onset of fever, generally mild at first — Within one to two days, the appearance of black or dark swellings — boubones — in the groin, armpits, neck, behind the ears, or on the thigh — Progressive lethargy, hallucination, and (in some patients) violent delirium — Many patients died within five days of symptom onset; some died within one day; a small minority recovered after the swellings burst

The description corresponds to the modern clinical pattern of bubonic plague with secondary septicaemic and pneumonic forms. The boubones are inguinal and axillary lymph nodes enlarged by infection with Yersinia pestis.

What it killed

Procopius records that the peak mortality in Constantinople was approximately 5,000 deaths per day. He later says some sources gave figures up to 10,000 per day at the worst week. The city’s mass graves filled. The civil administration of corpse-burial collapsed. Bodies were piled in the Towers of Sycae on the opposite shore of the Golden Horn and burned. Justinian himself contracted the disease but survived.

The empire-wide death toll over the 541-549 CE first wave is estimated by modern historical-demographic reconstruction at 25 to 50 percent of the affected population. Lester Little’s Plague and the End of Antiquity (2007) gives a range of 25-40 percent; Peter Sarris’s more recent work suggests the upper end of the range is the more plausible estimate.

The plague returned in successive waves at irregular intervals over the next two centuries. The last documented outbreak of the First Pandemic is dated approximately 749 CE — about 208 years after the initial outbreak. The total cumulative mortality across the First Pandemic is conventionally estimated at 30-50 million deaths.

2013

The exact pathogen had been disputed since the 19th century. The conventional 20th-century identification was Yersinia pestis — the same bacterium that caused the 14th-century Black Death — but the identification was based on clinical-symptom matching rather than on direct evidence.

The German archaeological team led by Holger Wagner published in 2013 the first molecular confirmation. Skeletal remains from a 6th-century Bavarian burial site at Aschheim near Munich contained recoverable DNA of Yersinia pestis in the dental pulp of multiple individuals. The 2013 analysis confirmed the identification and produced a partial genome of the 6th-century strain.

The 2014 Lancet Infectious Diseases publication (Wagner et al.) compared the Aschheim genome to modern Yersinia pestis strains and to the 14th-century Black Death strain (which had been independently sequenced from 2010 onwards). The conclusion was that the First Pandemic strain (the “LNBA” lineage) and the Second Pandemic Black Death strain are both descendants of a common Asian-steppe ancestor but were independent introductions to Europe approximately 800 years apart. The First Pandemic strain went extinct in the wild after the 8th century.

Political consequences

The plague reduced Justinian’s capacity to consolidate the reconquered Western territories. Italy was largely lost to the Lombards by 568 CE. North Africa was lost to the early Islamic conquests in the 690s-700s CE. The Eastern Roman Empire’s tax base and military recruitment shrank to a fraction of the early 540s peak.

Several modern historians (most notably Mischa Meier and Peter Sarris) argue that the First Pandemic, rather than the conventionally-cited barbarian invasions or the rise of Islam, was the single largest factor in the structural collapse of late Roman institutions across the Mediterranean. The argument is contested but increasingly mainstream.

Justinian died in November 565 CE, aged 83, of natural causes. His wife Theodora had died of cancer of plague-era Constantinople in June 548. He had outlived her by 17 years and had not remarried.