Young Henry Knox was spirited and inexperienced. Many of the leading characters in the birth of American democracy were young. Thomas Jefferson was 33 years old when he wrote the Declaration of Independence. Benjamin Rush, leader of the antislavery movement at the time, was 30 when he signed it. When war broke out and Henry Knox abandoned his book shop to looters and snuck out of Boston to join the militia, his new bride riding beside him with his sword sewn inside her cape, he was just 25.