While in the course of the 19th century, with the development of the railroad and steamship, the transport of people and goods fell out of the remit of the state post offices , the postal monopoly on letters , parcels and periodically printed documents remained .
The mail shelf was practiced differently in the countries of Europe, Asia and America. There was both the sole transport of mail by the state post offices and the state licensing to private companies. The mail shelf was later expanded to include telegraphs .
The last remnant of the post office shelf in Germany is the issuing of a license for mail transport up to 1,000 g by the Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railways in accordance with Section 5 (1) of the Postal Act .