This chapter is devoted to the development of postal systems. The author starts in the classical world, with several different systems, but particularly the Roman, and moves on to the European systems of the Renaissance on, to the big nationalised systems of the nineteenth century, and the heyday and subsequent decline of traditional postal services in the late twentieth century. On the way, the author discusses the medium used for letter-writing, infrastructure such as the roads, the postage stamp, and the organisation of multiple interconnecting postal services.