Established in the early 1800s and aided by people involved in the Abolitionist Movement, the underground railroad helped thousands of slaves escape bondage. By one estimate, 100,000 slaves escaped from bondage in the South between 1810 and 1850. Aiding them in their flight was a system of safe houses and abolitionists determined to free as many slaves as possible, even though such actions violated state laws and the United States Constitution.