Curses publicus was the courier service of the Roman Empire. It was created by Emperor Augustus to transport messages and officials from one province to another. A series of forts and stations were spread out along the major road systems connecting the regions of the Roman world. These relay points (or stationes) provided horses to dispatch riders, usually soldiers, and vehicles for magistrates or officers of the court. The vehicles were called calbulae, but little is known of them. A diplomata or certificate issued by the emperor himself was necessary to use the roads. Abuses of the system existed, for governors and minor appointees used the diplomata to give themselves and their families free transport. Forgeries and stolen diplomata were also used.

The curses operated in Italy and the more advanced provinces. There was only one in Egypt and one in Asia Minor, as Pliny's letters to Trajan attest. It was common for a village to exist every 12 miles or so, and there a courier might rest at large, privately owned mansiones. Operated by a manceps, or a business man, the mansiones provided food and lodging, and care and a blacksmith for the horses. The curses also used communities located along the imperial highways. These towns very often provided food and horses to messengers of the Legions, theoretically receiving reimbursement, and were responsible for the care of their section of the Roman roads. Disputes arose naturally, and for a time the central administration participated more directly.

Costs for the curses publicus were always high, and its maintenance could not always be guaranteed. Around the time of Nerva, in the late first century, the general cost was transferred to the Fiscus (treasury). Further centralization came during the reign of Hadrian, who created an actual administration under a prefect, who bore the title praefectus vehiculorum. Provinces were always in touch with Rome and one another. The Imperial Post gave the legions the capacity to summon reinforcements and provide status reports before any situation deteriorated to badly. The average citizen sent letters and messages to friends across the sea through slaves and traveling associates. Most news reached its destination eventually.