It’s common wisdom that William Henry Harrison delivered one killer of a speech after being sworn in as the ninth president of the United States—and it had nothing to do with anything he said.

Ignoring the advice of vigilant mothers everywhere, “Old Tippecanoe” swore off his overcoat, hat and gloves while giving his inaugural address on a freezing, wet winter day. And in a quest to prove his virility while silencing critics who thought him an intellectual lightweight, the 68-year-old Harrison definitely overcompensated by delivering a whopping 8,445-word speech that droned on for nearly two hours. Many believe that history’s lengthiest inaugural address led directly to the briefest of presidencies as Harrison died exactly one month later on April 4, 1841—with the official cause listed as pneumonia.

It is unlikely, however, that the long-winded speech caused the president’s death because he didn’t become sick, complaining of anxiety and fatigue, until more than three weeks after his inauguration. Plus Harrison’s lung ailments didn’t arise until the fifth day of his illness and were not nearly as relentless or progressive as the severe abdominal discomfort and constipation he experienced.

After taking a fresh look at the case, Jane McHugh and Dr. Philip A. Mackowiak of the University of Maryland School of Medicine wrote in a 2014 edition of the journal Clinical Infectious Diseases that Harrison likely died from enteric fever, not from a fatal chill contracted during the inauguration.

The pair pointed to contaminated drinking water as the true cause of Harrison’s demise. Before 1850, the sewage of Washington, D.C., was dumped in a fetid marsh just seven blocks upstream from the White House’s water supply, and the researchers surmised that bacteria seeped into the drinking water and caused the president’s severe gastroenteritis. Harrison’s history of dyspepsia put him at additional risk to the tainted water, which the authors noted may have also contributed to the death of another president, Zachary Taylor.

Access hundreds of hours of historical video, commercial free, with HISTORY Vault. Start your free trial today.