Siege of Fort Pitt

Fort Pitt endured a lengthy blockade across June and July of 1763, in the location that would become present-day Pittsburgh, Pennsylvania, United States. This confrontation formed one chapter of Pontiac's War, the broader campaign through which Native Americans sought to push Anglo-Americans out of the Ohio Country and the Allegheny Plateau, since colonists had gone back on the promises and treaties they had made to withdraw once the French were beaten. Despite pursuing both negotiation and armed pressure, the Native American coalition never succeeded in dislodging the Anglo-American presence from the fort.

What makes this episode particularly notable is the suspicion that biological warfare was attempted there. William Trent, along with Simeon Ecuyer, a Swiss soldier serving as a mercenary for the British, are believed to have handed Native American emissaries objects taken from a smallpox infirmary, disguising them as gifts in hopes that the disease would spread to neighboring tribes. Whether this scheme actually worked remains uncertain. What is clear is that this transmission method proved far less efficient than respiratory spread, and separating any deliberate contagion from outbreaks already tied to earlier interactions with colonists remains a genuinely difficult task.

Biological warfare

Disease struck near Fort Pitt in the spring of 1763, and smallpox soon took hold within the fort itself, prompting the establishment of a hospital there for infected soldiers. This was not the first time the illness had touched the region; Ohio tribes had suffered an outbreak roughly a decade earlier, since smallpox tended to resurface every twelve years or so. John McCullough, who spent time as a captive, recounted that warriors from a Mahoning village who had raided a settlement in the Juniata valley brought the sickness back with them, and some later died from it.

A 1924 issue of the Mississippi Valley Historical Review printed the journal of William Trent, a merchant and fur trader who held a captain's commission at Fort Pitt. His entry from June 24, 1763 describes an encounter with two Delaware men at the post: he noted giving them two blankets and a handkerchief taken from the smallpox hospital, adding his hope that the gesture would produce its intended result. For generations afterward people assumed smallpox spread easily through contaminated fabric like clothing or bedding, yet A. R. Rao's careful studies conducted in the 1960s, during smallpox's final years of widespread occurrence, turned up nothing to support this belief. Rao instead concluded the illness traveled through the air, spread by inhalation.

The linen used to wrap the two blankets and handkerchief taken from the infirmary suggests the items were likely soiled and unwashed. A document belonging to Trent's trading company surfaced in 1955, containing a bill for the handkerchief, the pair of blankets, and the wrapping cloth meant for the Native visitors, with the cost bearing Ecuyer's signature. Ecuyer had limited experience at the time, holding his captaincy only since April of the previous year and having assumed command of the fort that November. Given his greater familiarity with the disease and his role in founding the smallpox hospital, Trent was probably the scheme's principal architect. Alexander McKee, who was of mixed heritage, helped relay communications during the exchange, though he may have remained unaware of what the bundle contained. Neither General Amherst nor Colonel Bouquet had any hand in devising this plan.

The gathering unfolded on June 24, after two Delaware men had approached McKee the previous evening asking to talk with him come morning. Discussions took place just beyond the walls of Fort Pitt, involving Ecuyer, McKee, a man called Turtle's Heart, and a chief identified as Mamaltee. The Delaware representatives urged those sheltering inside the fort to abandon it, a suggestion Ecuyer flatly turned down while insisting that help was on its way and the garrison could withstand any siege. After the two men consulted with their chiefs, they came back pledging continued loyalty to what they called the chain of friendship, though their sincerity seemed doubtful. They had requested provisions, including food and drink, to bring back home, a common enough ask, though Ecuyer's response proved unusually lavish. Turtle's Heart and his fellow representative departed with substantial supplies, roughly 600 rations, among which sat the linen-wrapped blankets and handkerchief.

When Trent encountered the same group of delegates again a month later on July 22, none appeared to have fallen ill. His account from that date names Gray Eyes, Wingenum, Turtle's Heart, and Mamaultee, who crossed the river to report that their chiefs remained in council awaiting the arrival of Custaluga.

Gershom Hicks, fluent in Delaware and possessing some knowledge of Shawnee as well, testified that between spring 1763 and April 1764 approximately a hundred Native people from various nations, Lenni Lenape and Shawnee among them, perished from smallpox, marking this as a fairly limited outbreak overall. David McClure, writing after a visit to Pittsburgh some years later in a journal eventually published in 1899, recorded being told that when the Delaware, Shawnee, and other groups treacherously besieged Fort Pitt in 1764 during a supposed time of peace, those tr