On this day in 1820, Massachusetts lost over 30,000 square miles of land as its former province of Maine gained statehood. Mainers had begun campaigning for statehood in the years following the Revolution. The Massachusetts legislature finally consented in 1819. What no one in either Massachusetts or Maine foresaw, however, was that Maine's quest for statehood would become entangled in the most divisive issue in American history — slavery. Most Mainers supported abolition. They were dismayed that their admission to the Union was linked to the admission of Missouri as a slave state. This controversial "Missouri Compromise" preserved — for a few more decades — the delicate balance between pro- and anti-slavery forces in the U.S. Congress.