The Mediterranean Sea in the early-modern age arguably was what the world’s oceans became in later times, a laboratory for what would produce the reality of global commercial and political competition. By the eighteenth century, this comparison was already made by political writers who looked into the future and saw a further mixing of private and public interests and the greed and ambition of European nations giving rise to exploitation and the submission of other territories. Yet, if ‘free trade’ became the vehicle for the European colonisation of the world, its institutional and geographical ancestry remains uncertain. In this introductory article, we trace the development of political and economic functions performed by free ports in the Mediterranean from the sixteenth to the twentieth century. The chapter discusses the ‘primitive’ function of the free port to attract goods and create markets in barren and depopulated territories and brings together hitherto separate historiographies into a general perspective and genealogical narrative of the ‘invention’ of free trade.