A form of individualist anarchism was found in the United States as advocated by the Boston anarchists. Some Boston anarchists, including Benjamin Tucker and Lysander Spooner, identified themselves as socialists, a label often used in the 19th century in the sense of a commitment to improving conditions of the working class (i.e. the labor problem). The Boston anarchists such as Tucker and his followers are also considered socialists due to their opposition to usury. By around the start of the 20th century, the heyday of individualist anarchism had passed, On the other hand, anarchist historian George Woodcock describes Spooner's essays as an "eloquent elaboration" of Josiah Warren and the early American development of Proudhon's ideas and associates his works with that of Stephen Pearl Andrews. Woodcock also reports that both Spooner and Greene had been members of the socialist First International.