Owenism is the utopian socialist philosophy of 19th-century social reformer Robert Owen and his followers and successors, who are known as Owenites. Owenism aimed for radical reform of society and is considered a forerunner of the cooperative movement. The Owenite movement undertook several experiments in the establishment of utopian communities organized according to communitarian and cooperative principles. One of the best known of these efforts, which were largely unsuccessful, was the project at New Harmony, Indiana, which started in 1825 and was abandoned by 1829. The Owenites were mentioned by Karl Marx in The Communist Manifesto.