Born Nov. 21, 1818, in Aurora, N.Y.; died Dec. 17, 1881, in Rochester, N.Y. American ethnologist and archaeologist, historian of primitive society, and progressive public figure. Member of the National Academy of Sciences of the USA (1875).

An attorney by profession, Morgan practiced law and later engaged in commerce. He early became interested in the Iroquois. Morgan founded a society for the study and aid of the Indians (1840); he decried the despoilment, discrimination, and extermination of Indians in the USA. In 1847 he was adopted by the Seneca, an Iroquoian tribe, under the name “One Lying Across” (that is, across the boundary between the Indians and the Whites).

The League of the Iroquois (1851), Morgan’s first major work, remains to this day the most important study of the Iroquois. In later works, most notable of which was Ancient Society, or Researches in the Lines of Human Progress From Savagery Through Barbarism to Civilization (1877; Russian translation, 2nd ed., 1934), Morgan emerged primarily as a historian of primitive society who asserted the ideas of the unity of mankind and its progressive development. His view of the clan as the universally and historically basic unit of primitive society occupied a central position in his theories. Related to this were his theses of the development of property from collective to private forms and of the evolution of the family and marriage from group to individual forms.

Morgan also worked out a scientifically valid periodization of primitive history, subdividing it into periods of savagery and barbarism and each of these into three subperiods. The most prominent proponent of evolutionism in ethnology, Morgan was in fact able to move away from evolutionism and, in the words of F. Engels, “within the bounds of his own field independently rediscovered, in Marxist fashion, the materialist understanding of history” (K. Marx and F. Engels, Soch., 2nd ed., vol. 36, p. 97).

Morgan’s ideas are still the subject of a controversy between the progressive and reactionary trends in ethnology. The data of modern ethnology and archaeology indicate that a number of Morgan’s minor theses require greater clarification, but his theories about primitive society retain their significance and continue to be developed by Marxist science.