The Twentieth-Century Origins of the Medieval Lex Mercatoria Thesis

This article reappraises the early intellectual formation of the medieval "lex mercatoria"thesis: the idea that the international merchants of medieval Europe (or perhaps beyond) enjoyed a universal, autonomous, and customary body of commercial law created and administered by themselves. The debate over its existence, raging for at least 120 years, shows no signs of slowing, in part because the idea is of undoubted usefulness to both proponents (so-called "mercatorists") and critics. The article offers a new account of the origins of this idea and looks to disaggregate different mercatorist conceptions. Revising the conventional genealogy that traces the theory through the work of Berthold Goldman to the nineteenth-century German scholar Levin Goldschmidt, who is much misunderstood in Anglophone scholarship, it argues that the idea's powerful re-emergence in the second half of the twentieth century was mediated through two distinct channels, one centred around the British-German jurist Clive Schmitthoff and the other around the British historian William Mitchell. The latter yoked Goldschmidt's emphasis on the medieval merchant class as a source of legal innovation to a thoroughly Anglophone concept: the "law merchant". Critics, however, have engaged primarily with Schmitthoff's conception, whose "strong"mercatorist argument was not only unusually forthright but reoriented the debate to focus on commercial law's supposed autonomy from the law of territorial states, an even less plausible proposition in historical terms.