An itinerarium (plural: itineraria) was an Ancient Roman road map in the form of a listing of cities, villages (vici) and other stops, with the intervening distances. One surviving example is the Peutinger Table (Tabula Peutingeriana); another is the Antonine Itinerary.
The Romans and ancient travelers in general did not use maps. They may have existed as specialty items in some of the libraries, but they were hard to copy and were not in general use. On the Roman road system, however, the traveller needed some idea of where he or she was going, how to get there, and how long it would take. The itinerarium filled this need. In origin it was simply a list of cities along a road: “at their most basic, itineraria involve the transposition of information given on milestones, which were an integral feature of the major Roman roads, to a written script.” It was only a short step from lists to a master list. To sort out the lists, the Romans drew diagrams of parallel lines showing the branches of the roads. Parts of these were copied and sold on the streets.
Source: Itinerarium – Wikipedia