Siege of Fort Pitt Siege of Fort Pitt The Siege of Fort Pitt took place during June and July 1763 in what is now the city of Pittsburgh, Pennsylvania, United States. The siege was a part of Pontiac's War, an effort by Native Americans to remove the British from the Ohio Country and Allegheny Plateau after they refused to honor their promises and treaties to leave voluntarily after the defeat of the French. The Native American efforts of diplomacy, and by siege, to remove the British from Fort Pitt ultimately failed. This event is best known as an early instance of biological warfare, where
Siege of Fort Pitt become by 1763 and how far British officers were willing to go in ignoring their own soldiers' code of warfare. A devastating smallpox epidemic plagued Native American tribes in the Ohio Valley and Great Lakes area through 1763 and 1764, but the effectiveness of these instances of efforts to spread smallpox remain unknown. After extensive review of surviving documentary evidence, historian Francis Jennings concluded the attempt at biological warfare was "unquestionably effective at Fort Pitt"; Barbara Mann deduced "it is important to note that the smallpox distribution worked"; Howard Peckham noted the resulting fatal epidemic "certainly affected their vigorous prosecution