Siege of Fort Vincennes

The Siege of Fort Vincennes (also known as the Siege of Fort Sackville), took place during the American Revolutionary War from the 23–25 February 1779, near present-day Vincennes, Indiana between a militia force led by Col. George Rogers Clark and a British force led by Governor Henry Hamilton. On 23 February an army of patriot militants surrounded the British occupied fort of Vincennes, where some 90 soldiers were stationed. The Patriots, outnumbered at the time, tricked the British and their Indian allies by dividing their army in groups of 10, to create the impression that they had an army of 1,000. In response to this the Indians retreated leaving the British army to defend themselves. After 3 days of intense fighting the British defenders finally surrendered the fort to the Patriots; amazingly, Clark's army was said to have taken the fort without losing a single soldier. After the Patriots won the battle, the British army in the Illinois territory was completely defeated and many Native Americans stopped raiding American settlements in Kentucky in response to the British absence.

Background
In July of 1778, Clark's army successfully captured all British outposts across the Illinois territory (including Vincennes), without firing a shot. In response to this British Governor Henry Hamilton departed from the British-held Fort Detroit on 7 October with an army of 200 British regulars and 300 Indian warriors. Clark, with minimal men, left a few soldiers to defend Vincennes once he captured it. On 17 December, Hamilton's army attacked the fort, forcing the Patriot commander Leonard Helm and a few soldiers to surrender without a fight. Once Hamilton captured Vincennes in December, much of his army went back to Detroit for the winter leaving him with an army of 90 British regulars and 200 Indians. Hamilton's plan was to stay in Vincennes until Spring, then lead an offensive to retake the remaining forts. When Clark heard about the loss in Vincennes he departed in midwinter hoping to surprise the British army and recapture Vincennes.

Siege
Clark's army finally arrived in Vincennes on 23 February 1779, after 1 month of marching across Illinois in the middle of winter. Clark knew he was outnumbered, so he divined a plan to make it seem like he had more than 1,000 men. He did this by separating his army into units of ten with each unit carrying an American flag (symbolizing a company of a hundred men). The British Native American allies really believed that Clark had 1,000 men, so they abandoned Hamilton's army, leaving him with only his garrison of 90 regulars. Clark's army easily secured the town of Vincennes without any resistance; many of the townspeople were sympathetic to the Patriots and told them that the British were still unaware of their presence and that they were all in the fort.

The first shots were later that day when the Patriots opened fire at the fort, surprising Hamilton when a bullet came through his window killing one of his officers. Fighting was intense for both sides until Clark requested Hamilton's surrender. Hamilton refused, thinking Clark was a barbarian from his previous executions and raids on Native American villages. At one point the defenders attempted to fire artillery at the Patriot lines, but the Patriot fire was so precise that the British gunners were unable to use their cannons. On 24 February, a small party of some 15-20 Indian warriors with 2 French partisans arrived at Vincennes, meeting besiegers. A small skirmish occurred killing 2 Indians, wounding 3, and capturing 8. Clark wanted to make an example for the Indian prisoners to stop raiding Kentucky settlements, so he ordered 4 to be tomahawked to death in front of the fort. Hamilton horrified witnessing the executions himself decided to meet Clark in the town church later that day for peace talks. Hamilton agreed to an unconditional surrender and the next day Hamilton raised the American flag over Vincennes and walked out of the Fort with 79 of his men. Clark renamed the fort "Patrick Henry", and he ordered for Hamilton and the rest of his army to be sent to a prisoner of war camp in Virginia.

Cannon Incident
On 25 February once the Patriots won control of Fort Vincennes, in celebration a six-pound cannon was fired. Some nearby cannon cartridges accidentally ignited, resulting in a massive explosion badly wounding Patriot commander Joseph Bowman, 4 privates, and a British soldier. Bowman died a few weeks later from his wounds, he was the only Patriot officer to have been killed in the Illinois campaign. It's unknown what exactly caused the explosion in the first place, but some say the British tampered with it after the fort was captured.

Aftermath
Once the Patriots gained control of Vincennes, they seized control of the entire Illinois territory (which is present-day Illinois and Indiana). This helped stop Indian raids on the Kentucky settlements by neutralizing the British influence on Native American tribes. This battle was seen as a brilliant military strategy used by Clark, by creating the impression that he had more than 1,000 men. By doing so, he won the battle outnumbered and he took control of the Illinois territory very easily, without losing a single soldier in combat. This battle also stopped the British advance towards Virginia: if Clark had not defeated Hamilton's army in Vincennes the British could have easily taken over many Kentucky settlements and eventually created another battle front in the war.