Early followers of George's philosophy called themselves single taxers because they believed the only economically and morally legitimate, broad-based tax is on land rent. As a term, "Georgism" was coined later, although some modern proponents prefer the less eponymous "geoism", leaving the meaning of "geo-" (from the Greek "ge", meaning "earth") deliberately ambiguous. "Earth Sharing", "geonomics" and "geolibertarianism" are used by some Georgists to represent a difference of emphasis or divergent ideas about how the land value tax revenue should be spent or redistributed to residents, but all agree that economic rent must be recovered from private landholders. Within the libertarian left, George and his geoist movement influenced the development of democratic socialism, especially in relation to British socialism and Fabianism, along with John Stuart Mill and the German historical school of economics. George himself converted George Bernard Shaw to socialism and many of his followers are socialists who see George as one of their own. Individuals described as being in this left-libertarian tradition include George, Locke, Paine, William Ogilvie of Pittensear, Spencer and more recently Baruch Brody, Ellerman, James O. Grunebaum, Otsuka, Steiner, Vallentyne and Van Parijs, among others. Roberto Ardigò, Hippolyte de Colins, George, François Huet, William Ogilvie of Pittensear Paine, Spencer and Léon Walras are left-libertarians also seen as being within the left-liberal tradition of socialism.