Answer:
They were forced to leave their lands and move west.
During the 1830s, the Southern Native tribes were forcibly removed from their ancestral lands in the southeastern United States and moved to Indian Territory (present-day Oklahoma) as a result of the Indian Removal Act of 1830. This law, signed by President Andrew Jackson, authorized the forced relocation of Native Americans to Indian Territory and was implemented by the U.S. government through a series of forced removals, including the infamous Trail of Tears. This policy resulted in the displacement of tens of thousands of Native Americans and the loss of their land and communities.