when did the missouri compromise happen
1 In 1819, Maine applied for statehood. Then a compromise developed: Maine could join as a free state to balance out Missouri joining as a slave state.  By 1820, the compromise had been realized. First, Missouri and Maine would be admitted to the Union, one as slave and one as free. In addition, the remaining territories would be divided into free and slave at the 36Â°30' parallel. This compromise became viewed as sacred by both sides.