Complex sentence: The Mississippi Chippewa, along with the Red Lake Band, Pillager Band and the Lake Superior Band, entered into the Treaty of St. Peters in 1837, ceding to the United States what now is part of northern Wisconsin and east-central Minnesota.
Split into simpler sentences: The Mississippi Chippewa, along with the Red Lake, Pillager and the Lake Superior bands, entered into the Treaty of St. Peters in 1837. They ceded to the United States what is now part of northern Wisconsin and east-central Minnesota.