During the Middle Ages the idea of common ownership was theoretically maintained by church Fathers and their followers, on the basis of Christ’s teaching which perpetually sympathized with the poor. St. Fathers regarded community of goods as the ideal order of society, private property as a necessary evil, trade as an occupation hardly compatible with the character of a devout Christian, and the receipt of interest for the use of money as altogether sinful. They said that individual property is contrary to the Divine Law, therefore _Omnia debent esse communia_. These principles could never be applied with logical severity. Ecclesiastics theoretically preached equality of men, and in practice they were the wealthiest class among other classes. Roderigo Borgia, later Pope Alexander VI, was one of the richest men of his time[66]. The luxury, immorality and privileged wealth of clergy caused the Reformation, but the Reformation could not restrain the clergy from acquiring immense private possessions. Communism of the Middle Ages was then a pure utopia, as it is today. In the philosophy of the 17th, 18th, and 19th centuries the institution of private property was justified by many jurisconsults, reformers, and philosophers who, based their teachings on human nature. Among these are significant theories of Grotius, Locke, Hobbes, Thiers[67], and Coulanges[68]. In opposition to these writers we find, throughout the French Revolution and later on, the writers who assailed private property as pernicious. Rousseau expressed himself with all his fervid eloquence upon this theme, and he found a large public to sympathize with his declamations. Rousseau was the inspirer of those revolutionary writers, inferior in genius but equally daring, who helped to diffuse his doctrines. Mirabeau and Robespierre were also Rousseau’s adherents. Even the socialists, though they have dropped some of his first principles and have adopted some of the conclusions of modern science, have inherited no small portion of his spirit[69]. In America we find many of Rousseau’s followers who were inspired by philosophers of the French Revolution. Among these followers is Henry George[70], and in Russia, Tolstoy. The difference between these two reformers is that George would put the rent of real property in the hand of government for better and more righteous taxation than is now the case. Tolstoy, meanwhile, is against all taxation, because it can only be collected by force, and all force is forbidden by Christ. George is for nationalization of land, Tolstoy for full communalization, against all government and all state ownership[71].