Before achieving official admission to the Union as the thirty-fourth U.S. state in January 1861, the territory comprising modern-day Kansas was organized under federal administration as the Kansas Territory, created following the highly contentious Kansas-Nebraska Act of 1854. This turbulent pre-statehood era was famously characterized by violent political and ideological clashes between pro-slavery and anti-slavery settlers, earning the region the bloody moniker Bleeding Kansas. Going further back into historical exploration and indigenous eras, the land was claimed by France and Spain as part of the vast Louisiana Purchase territory, taking its name from the Kansa or Kaw indigenous people who historically inhabited the fertile river valleys of the region.