These ideas persisted for a long time, and some even still today. Ideas slowly began to change throughout the 1900s. Lewis Henry Morgan (1818-1881) was an American Anthropologist who was interested in kinship systems and social evolution. He became deeply interested in the Native American populations, concerned about their struggles with colonialism and oppression. He was adopted by the Seneca Native American tribe, and worked closely with Ely S. Parker, a Seneca member to write "The League of the Iroquois". While Morgan gave Parker some initial credit for his contribution to the publication, Morgan still often took credit for the work, and even at times pushed harmful Native American Stereotypes. Sir Edward Burnett Tylor (1832-1917) was a British Anthropologist, and often cited as the founder of cultural anthropology. He introduced the theory of progressive evolution, the idea that cultures evolved from primitive to modern, and that those considered primitive were just less evolved peoples than the western people who had modern culture, similar to the ideas of Darwin. Earnest Hooton (1887-1954) was an American Physical anthropologist, who spent his career advocating for eugenics and attempting to separate races into categories based on skeletal features and measurements. He sat on a Committee on the Negro, which studied the anatomy of Black people to try and prove that they were an inferior subgroup. 