The Origin of the Family, Private Property and the State is an 1884 philosophical treatise by Friedrich Engels. It is partially based on notes by Karl Marx to Lewis H. Morgan's book Ancient Society (1877). The book is an early historical materialist work and is regarded as one of the first major works on family economics. The writing of The Origin of the Family began in early April 1884, and was completed on 26 May. Engels began work on the treatise after reading Marx's handwritten synopsis of Lewis H. Morgan's Ancient Society; or, Researches in the Lines of Human Progress from Savagery, Through Barbarism to Civilization, first published in London in 1877. Engels believed that Marx had intended to create a critical book-length treatment of the ideas suggested by Morgan, and aimed to produce such a manuscript to fulfill his late comrade's wishes