Ancient Society
In the years that followed, Morgan developed his theories. Combined with an exhaustive study of classic Greek and Roman sources, he crowned his work with his "magnum opus" "Ancient Society" (1877). Morgan elaborated upon his theory of social evolution. He introduced a critical link between social progress and technological progress. He emphasized the centrality of family and property relations. He traced the interplay between the evolution of technology, of family relations, of property relations, of the larger social structures and systems of governance, and intellectual development.