"Garrison was the first to proclaim this principle as a rule for the organization of man's life," Tolstoy acknowledged, and described the "spiritual joy" with which he discovered the existence of kindred thinkers in Garrison, Ballou and the earlier pacifist William Dymond. Later in his life Tolstoy added to the list of Americans who had influenced him, the names of Emerson, Thoreau and Walt Whitman, among others. He was also influenced in his economic views by Henry George's Progress and Poverty. In turn, Tolstoy exerted a considerable influence on American intellectuals, and his ideas inspired a revitalization of the American peace movement.