An ostensibly democratic idea, popular sovereignty stated that the inhabitants of each territory or state should decide whether it would be a free or slave state; however, this resulted in immigration "en masse" to Kansas by activists from both sides. At one point, Kansas had two separate governments, each with its own constitution, although only one was federally recognized. On January 29, 1861, Kansas was admitted to the Union as a free state, less than three months before the Battle of Fort Sumter officially began the Civil War.