2. George Washington: Washington's Continental army joined forces with the French army under Rochambeau, forming a combined force that outnumbered the British.
3. Siege Tactics: The combined forces set up fortifications around Yorktown, preventing Cornwallis from moving or escaping.
4. Lack of Supplies: The siege cut off Cornwallis' supply lines, leaving his troops short of food, ammunition, and other necessities.
5. Disease: Diseases such as smallpox weakened Cornwallis' army and reduced their fighting strength.
6. Morale: The British morale declined as they realized their situation was hopeless, with no relief in sight.
These factors combined to force Cornwallis' surrender on October 19, 1781, effectively ending major combat operations in the American Revolutionary War.