The Tabula Peutingeriana

The Tabula Peutingeriana is the only unique copy of what once must have been readily available road maps for travelers using the Cursus Publicus, the Roman Empire's system of stables and inns along Roman roads that allowed rapid travel to approved users. 

Think of it as the ancient equivalent of the map to the London Underground.

 While the Tabula Peutingeriana itself seems to reflect the state of the Cursus Publicus in a 5th Century AD time frame, it is still a valuable window into the functional nature of the Cursus throughout its existence.

In the novel, In Saecula Saeculorum, a group of high school Latin students are sent back in time on a mission to save the world. They need to use the Cursus Publicus in order to travel from Britannia to Rome and back in just under a month. And they do acquire a 2nd century AD version of the Tabula Peutingeriana which helps them plan their travels.

If you would like to explore the Tabula Peutingeriana in more depth, click on this link and you can zoom in on every fascinating inch of this ancient relic. Of particular interest is the fact that the Romans really were aware of such far-flung places as China, since they do include them at the extremities of the map!