One of the more impressive things about Alexander the Great is that the military genius did it all before the age of 32.

While details differ, the general outline of Alexander’s death in the city of Babylon in 323 B.C., is roughly the same: Alexander spent a night drinking with the naval officer Nearchus, then hit the booze the following day with his buddy Medius of Larissa. Soon after, a fever struck and he complained of acute pain in his back as if being stabbed by a spear. The fever worsened and he slowly became unable to move and then unable to speak. When he drank wine, he only became thirstier. The paralysis grew, and eventually he could not raise his head.

After he died, his body did not decompose for six day, according to Plutarch, who wrote a biography of Alexander hundreds of years after his death in the 2nd century A.D. “His body, although it lay without special care in places that were moist and stifling, showed no sign of such destructive influence, but remained pure and fresh,” he wrote, which some took as a sign that he was not poisoned and others saw as a sign of divinity.

This is the established narrative on what felled Alexander, as pulled from several secondary sources which relied on ancient accounts that are now lost.

But to Katherine Hall of the Dunedin School of Medicine at the University of Otago in New Zealand, Alexander’s symptoms resembled a case of a neurological disorder called Guillain-Barré Syndrome (GBS), in which the body’s immune system attacks the nerves, leading to eventual paralysis. She suggests Alexander contracted a Campylobacter pylori infection, the “most frequent cause for GBS world-wide,” which set off the autoimmune disorder, a theory she presents in The Ancient History Bulletin.

While other theories for what killed Alexander have lingered on the fever and pain, GBS fits all the symptoms, including the spread of paralysis, the fact that he seems to have maintained a sound mind even though he could not speak, even why his body did not decompose right away, she explains. “The elegance of this diagnosis for the cause of his death is that it explains so many of otherwise diverse elements and renders them into a coherent whole,” she writes in the article.

The most disturbing part of Hall’s theory is that Alexander probably was probably still alive when he was declared dead, which explains why his body stayed so "fresh." As Hall lays out in her argument, “it is necessary to understand two determinants of survival: the oxygen needs of the body, and the ability of the body to absorb oxygen without any muscular effort.”

Once he was extensively paralyzed, that could have lowered his body’s demand for oxygen. His pupils would have been fixed and dilated, and his body may not have been able to regulate his temperature properly, making him cold. Because physicians in the ancient world relied on breath not pulse to determine death, Alexander’s death may have been announced prematurely.

“I wanted to stimulate new debate and discussion and possibly rewrite the history books by arguing Alexander’s real death was six days later than previously accepted,” Hall explains in a press statement. “His death may be the most famous case of pseudothanatos, or false diagnosis of death, ever recorded.”

Without a time machine, Alexander’s actual remains (the location of his tomb is still unknown) or a totally accurate account of the death, it’s impossible to prove the cause of his death. Scholar Candida Moss writes for The Daily Beast there are several major issues to consider, including Hall’s reliance on Plutarch’s narrative of events, and using “vague reports” to diagnose ancient figures.

Owen Jarus over at LiveScience spoke to several scholars not involved in the research who express similar sentiments. While they agree that the GBS diagnosis is plausible—the incidence rate is higher in modern-day Iraq, where Babylon was located than other places—the evidence is unreliable. Pat Wheatley, a professor of classics at the University of Otago, for instance, also points out that it’s difficult to trust accounts written hundreds of years after the incident, especially when we can't examine the source material.

Still, it’s fun to speculate, and researchers have developed something of a cottage industry of diagnosing the ailments of historical figures to stimulate new discussion, including Michelangelo’s arthritis, Jane Austen’s Addison’s disease and Abraham Lincoln’s depression and, of course, sanguivoriphobia, which led him to live that surprising double life.