Whereas the classic vision of the history of legal sources focused on custom as primary the element, recent works have shown the multiplicity of historical situations in which customary law was forged after other legal techniques. For several years, studies on colonial law have accepted this idea of an invented tradition; new research on European customary law during the Middle Ages supports the same thesis. This historiographical evolution reinforces the argumentation of legal positivists who consider law an invented technology. Based on these historical works and a combination of “secondary rules” and Bourdieu’s “legal field”, this article proposes a fresh perspective on Hart’s Concept of Law.