In September 1812, Indians from the Potawatomi and Miami tribes, led by Chief Winamac, undertook a campaign against Fort Wayne, commanded by Captain James Rhea.
The siege began on September 5 when Chief Winamac assaulted the fort from the east side and burned the homes of the surrounding village. The Indians constructed two wooden cannons and were able to trick the garrison into thinking they had artillery besieging the fort as well. When Rhea began to discuss ideas of surrender, two of his lieutenants decided he was unfit to continue his duties and relieved him of command. These two lieutenants then assumed command and continued to hold out in the fort until reinforcements arrived.
General William Henry Harrison, the newly appointed commander of the Northwest frontier, led a relief force of 2,200 soldiers to Fort Wayne, arriving on September 12. Harrison attacked and defeated the Indian force, lifting the siege. The Potawatami/Miami force retreated into Ohio and Michigan Territory. Harrison had originally arrested Rhea but allowed him to resign instead. He then placed Lieutenant Philip Ostander (one of the two lieutenants who had relieved Rhea) in command of the fort.
The siege of Fort Wayne prompted Harrison to order punitive expeditions against the Miami which culminated in the Battle of the Mississinewa. This Miami defeat at Fort Wayne, as well as that in Battle of Fort Harrison, caused the Miami warriors to lose confidence in their chiefs. Many of them turned instead to the influential leadership of Tecumseh and joined his confederacy.