The conception of property is usually moulded upon diverting historical and political-philosophical frameworks. The current interest on the commons illustrates these divergences when they come up between a ‘pure’ public and a ‘pure’ private form of ownership. This conceptual triad misleads by conflating private property with an absolute property right while equating public property with a centralised political regime. This article traces the republican conception of property in order to show how it draws a legal and philosophical continuum around different forms of ownership, based on a fiduciary principle underlying the relationship between the sovereign or principal (trustor) and its agent (trustee). Despite modern socialism apparently left aside the question of the commons, the republican-fiduciary rationale was reformulated according to the modern industrial capitalist society.