Simplify the following text for a Grade 17 native English-speaking person.
Original: The Five Civilized Tribes were the five Native American nations : the Cherokee , Chickasaw , Choctaw , Creek , and Seminole , which were considered civilized by Anglo-European settlers during the colonial and early federal period because they adopted many of the colonists ' customs and had generally good relations with their neighbors .
Simplified: The Five Civilized Tribes is the term applied to five Native American nations , the Cherokee , Chickasaw , Choctaw , Creek , and Seminole , considered civilized by white settlers during that time period because they adopted many of the colonists ' customs and had generally good relations with their neighbors .