Fort Pitt Museum Pitt, after William Pitt the Elder. As a result, in 1763 local Delawares and Shawnees took part in Pontiac's Rebellion, an effort to drive the British out of their territory. The Indians' siege of Fort Pitt began on June 22, 1763, but the fort was too strong to be taken by force. In negotiations during the siege, the commander of Fort Pitt gave two Delaware emissaries blankets that had been exposed to smallpox, in hopes of infecting the surrounding Indians and ending the siege. The effectiveness of this attempt is unclear. Outbreaks of smallpox had plagued Native Americans for years
Siege of Fort Pitt McClure would write in his journal, "I was informed at Pittsburgh, that when the Delawares, Shawanese & others, laid siege suddenly and most traitorously to Fort Pitt, in 1764, in a time of peace, the people within, found means of conveying the small pox to them, which was far more destructive than the guns from the walls, or all the artillery of Colonel Boquet's army, which obliged them to abandon the enterprise." 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