 For Roderick T. Long, libertarian socialists claim the 17th century English Levellers among their ideological forebears.Various libertarian socialist authors have identified the written work of English Protestant social reformer Gerrard Winstanley and the social activism of his group (the Diggers) as anticipating this line of thought.For anarchist historian George Woodcock, although Pierre-Joseph Proudhon was the first writer to call himself an anarchist, at least two predecessors outlined systems that contain all the basic elements of anarchism.