How did Alexander the Great die?

Alexander the Great died in June 323 B.C. in Babylon, in what is now Iraq, at age 32. By that time, he had conquered an empire that stretched from the Balkans to India. This empire collapsed shortly after his death, with his generals and officials carving it up into different kingdoms.

But how did Alexander the Great die? The answer has been a long-standing mystery in history and archaeology, but historical texts provide a few possibilities.

Related: Was Alexander the Great eaten by sharks? Inside the wild theories for what happened to the iconic ruler's body.

There are a number of ancient accounts of Alexander's death, but most come from centuries later. The writers Plutarch (who lived circa A.D. 46 to 120) and Arrian (who lived circa A.D. 88 to 160) both said that after a night of drinking, Alexander had a fever that gradually worsened in the days leading up to his death. An account written by Diodorus Siculus (who lived during the first century B.C.) claims that Alexander fell seriously ill after drinking and died shortly afterward.

Quintus Curtius Rufus, a writer who lived in the first century A.D., reiterates that Alexander died shortly after a night of drinking. Curiously, he stated that seven days after Alexander's death, his body had shown no sign of decay.

However, the surviving accounts of Alexander's death were written centuries after he died.

"We can never take our sources completely at face value, in part because all our surviving biographies about Alexander were composed hundreds of years after he died," Jeanne Reames, director of the ancient Mediterranean studies program at the University of Nebraska at Omaha, told Live Science in an email.

The ancient writers had access to "sources that were closer to the time — and which have since become lost — but they were not 'cut-and-pasting,'" Reames said, noting that all of the ancient writers and the sources they used had their own agendas.

What killed Alexander?

The mystery of what killed Alexander the Great is complicated by another factor: His body has never been found. That means there's little physical evidence that scientists can study to figure out how he died.

However, modern-day scholars have provided a wide range of theories to explain what killed Alexander. In a paper published in 2019 in the journal Ancient History Bulletin, Katherine Hall, a senior lecturer at the Dunedin School of Medicine at the University of Otago in New Zealand, proposed that Alexander the Great died of Guillain-Barré syndrome, a neurological disorder in which a person's immune system attacks their peripheral nervous system.

This condition could have left Alexander in a deep coma, which ancient doctors may have mistaken for death, Hall noted, adding that this may have been why Alexander's body didn't decay for so long. She also noted that accounts written by Plutarch and Arrian claim that Alexander was cognizant enough to be issuing orders until shortly before he fell unconscious. This is also common in people who have this disorder, Hall noted.

Another theory is that Alexander died of typhoid fever, a disease caused by the bacterium Salmonella enterica Typhi. The illness described by Plutarch and Arrian is similar to that of typhoid fever, Ernesto Damiani, a professor of physiopathology at the University of Padova in Italy, told Live Science in an email. Some historical records also suggest that at times, Alexander was in a stupor, which is "a state of drowsiness from which the subject can be awakened by elementary stimuli such as questions but into which he immediately falls again," Damiani said, noting that this is also commonly seen in typhoid fever patients.

Reames notes that Alexander's general health "was poor, thanks to multiple wounds, including one that almost killed him in India and probably left him with a partially collapsed lung." While his general health was poor Reames thinks that Typhoid fever is the best culprit for this death with malaria also being a possibility.

There are many more theories as to what killed Alexander, including pancreatitis, West Nile virus and chronic traumatic encephalopathy.

Was Alexander the Great poisoned?

Another theory is that Alexander was poisoned. Adrienne Mayor, a research scholar at Stanford University who has written extensively about Alexander, thinks this is the most likely cause of death. "Poisoning was immediately suspected by [Alexander's] closest companions, according to all the ancient historians who described [Alexander's] death" Mayor told Live Science in an email, noting that Alexander's mother, Olympia, also believed that he was poisoned.

Historical records don't mention anyone else falling ill, Mayor said. If Alexander had an infectious disease, others in Babylon also should have gotten sick at around the same time. Mayor says that the symptoms Alexander experienced matched poisoning from strychnine, these include high fever, which is mentioned by both Plutarch and Arrian. It also includes speechlessness caused by the jaw muscles being extremely stiff. Both Arrian and Plutarch mention that before Alexander lost consciousness he couldn’t speak, noting that Alexander’s commanders walked by with Alexander watching them but unable to talk. Another symptom that matches is paroxysmal contractions of muscles causing great pain. Diodorus Siculus mentions how Alexander suffered great pain after drinking from a cup of wine. Strychnine is a plant that grows in the highlands of India and Pakistan, so this poison could have arrived at Babylon through trade routes, Mayor said.

Paul Doherty, an independent scholar who has researched and written extensively on Alexander, also thinks poison killed Alexander. "My belief is that Alexander the Great was deliberately poisoned," Doherty told Live Science in an email. Historical records indicate that "Alexander was growing increasingly despotic and paranoid," Doherty said. Arsenic may have been the poison of choice, Doherty noted, and Ptolemy I Soter, who ruled Egypt after Alexander's death, may have been the culprit.

Will any new evidence emerge?

Although it's unlikely that Alexander's body will be found, more ancient historical records may emerge.

"The most promising possible source of new material is the virtual unravelling of the rolls from the Library at Herculaneum," Hall said in an email. These are scrolls that became carbonized after Mount Vesuvius erupted in A.D. 79. Technologies such as high-resolution CT scans and artificial intelligence are being used to read and decipher these scrolls.

There are "thousands of these rolls, so new documents might still arise," Hall said, but the process of scanning the rolls and reading them "is very slow and painstaking and might take decades to complete."

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