An itinerarium (plural: itineraria) was an ancient Roman travel guide in the form of a listing of cities, villages (vici) and other stops on the way, including the distances between each stop and the next. Surviving examples include the Antonine Itinerary and the Bordeaux Itinerary. The term later evolved and took wider meanings (see later meanings below).
These text-based route descriptions were complemented by physical markers on the ground in the form of the miliarium, or Roman milestone, which confirmed the distances along the described route.