In 1846, having failed to purchase his freedom, Scott filed a freedom suit in St. Louis Circuit Court. Missouri precedent, dating to 1824, had held that slaves freed through prolonged residence in a free state or territory, where the law provided for slaves to gain freedom under such conditions, would remain free if returned to Missouri. The doctrine was known as "Once free, always free". Scott and his wife had resided for two years in free states and free territories, and his eldest daughter had been born on the Mississippi River, between a free state and a free territory.