This is Mine
The first man who, having enclosed a piece of ground, bethought himself of saying «This is mine», and found people simple enough to believe him, was the real founder of civil society. From how many crimes, wars and murders, from how many horrors and misfortunes might not any one have saved mankind, by pulling up the stakes, or filling up the ditch, and crying to his fellows, «Beware of listening to this impostor; you are undone if you once forget that the fruits of the earth belong to us all, and the earth itself to nobody». But there is great probability that things had then already come to such a pitch, that they could no longer continue as they were; for the idea of property depends on many prior ideas, which could only be acquired successively, and cannot have been formed all at once in the human mind. Mankind must have made very considerable progress, and acquired considerable knowledge and industry which they must also have transmitted and increased from age to age, before they arrived at this last point of the state of nature.
Jean-Jacques Rousseau, in 'Discourse on the Origin of Inequality'