This article describes the development of the Swedish post in the 17th century as part of a "revolution in communications" that took place all over Europe. The fast introduction of postal organizations, newspapers and the diligence traffic entailed new modes of communication with long ranging consequences for the state and the societies. The article particularly emphasizes the pivotal role of the postmasters in this process. They were an expert group, whose economical and social credit was as important for their job as their intricate knowledge on the means to establish the necessary postal institutions. The article also discusses the way in which cultural agents used the post and what methods were taken to ensure the delivery of their letters.