To what period in history do free ports belong?

According to legend the first free port was Delos in Greek antiquity.

On what model exactly Livorno and Genua and other Italian free ports were established is disputed. From the early-modern age free ports ‘spread’ in Italy, then in Europe and the Atlantic and became a global phenomenon. The eighteenth century saw an outburst of new free ports being established, as did the nineteenth century. In the early twentieth century discussions were held in Britain and the United States about the prospects of turning a number of ports into free ports. These days SEZ’s (Special Economic Zones) function like free ports in a number of ways. In this project we want to reconstruct how over time certain functions became more and less prominent and whether the long history of free ports can actually be said to form one history or many different, disintegrated histories.