The Americo-Liberian settlers did not identify with the indigenous peoples they encountered, especially those in communities of the more isolated "bush." They knew nothing of their cultures, languages or animist religion. Encounters with tribal Africans in the bush often developed as violent confrontations. The colonial settlements were raided by the Kru and Grebo people from their inland chiefdoms. Because of feeling set apart and superior by their culture and education to the indigenous peoples, the Americo-Liberians developed as a small elite that held on to political power. It excluded the indigenous tribesmen from birthright citizenship in their own lands until 1904, in a repetition of the United States' treatment of Native Americans. Because of the cultural gap between the groups and assumption of superiority of western culture, the Americo-Liberians envisioned creating a western-style state to which the tribesmen should assimilate. They encouraged religious organizations to set up missions and schools to educate the indigenous peoples.