Classification of the Roman roads
Differently from the other monuments, roads will be classified as follows:
NUSR.STR.xxxx whereas: first 4 letters mean, as for the other monuments, “Numerazione Ufficiale dei Signa Romanorum” (Official Numeration of Signa Romanorum). “STR” is for “strade” or “stratae” (the same root is in the English word “street”) first “x” means the number of the road beginning from the Regina Viarum, the Appian Way, which is number 1 in the count. The following roads are considered following a clockwise order on their origin at the Servian Walls of Rome. With this method, after the Appian Way, we encounter the Via Ardeatina (which is number 2), and so on.
second “x” means a new road which begins from the road indicated by the previuos ‘x’; this order is given beginning from the Servian Walls, as well. E.g. for the Appian Way, its first ramification is the Via Latina (after less than a mile from the Porta Capena of the Servian Walls): this road will be NUSRSTR1100. The second road beginning from the Appian Way is Via Cavona, at its tenth mile; Via Cavona will be classified as NUSRSTR1200. When a road cross another road, it will be included just once, and given a string according to the firs time it is encountered.
third “x” means a road which beging from the road indicated by the previuos ‘x’. Same criterium for the fourth ‘x’ number.
Computation of distances is based on found miliar stones (roads from Rome measure from the Servian Walls, according to Pliny, Naturalis Historia, III.66)
Birth of roads
The development of the different civilizations in the world happened with different times from zone to zone, also with differences of several centuries and with distance from little tens or hundred of kilometers. As soon as man begins to explore systematically the surronding territory , he chooses to travel on a ridge, the line that unites the points more elevated of a relief. This choice allows to observe a more spacious portion of territory, holding constantly in visual contact with the actual point of departure and not losing the final objective. The ridges often finish suddenly at the convergence of two trenches, as a head, almost always sites of installations since the begin of history. The system of the Capitol and Palatine hills is just such a kind of situation, commonly known as the “ridge of Rome”, at the convergence Of two secondary course of water with the Tiber. Next step was the birth of the routes that allowed “to cut” a valley, as following the ridge, the road should be gone around. In the contexts where the valley was gone through by a stream or a creek there was also the possibility of a ford. After that, soon new itineraries borm, lying completely on the bottom of a valley or at half height. This needed a knowledge of the territory just of little superior to what already acquired. Meanwhile, with the growth of the installations, of their necessity of supplies and of the commercial exchanges between them, the net of the roads was articulating itself in a more complex way.
Tracing a road
In the determination of the route of Roman Roads, we find that they are amazingly straight for the most part which suggests that the Roman Roadbuilders had some means to maintain a straight building line, by some well determined means beyond that of the groma, which was certainly less accurate, lacking the necessary optical lenses, than more modern methods of surveying. However, it should not be considered that these road-lines were predrawn on maps since there is no evidence that Romans had maps which were accurate to scale. It may be relied upon, however, that the Roman Officers engaged in establishing road- lines were well versed in the geographical area where they were working, and understood the terrain aspects of the areas, as well as the required material for the construction of the road itself. Generally speaking, therefore, Roman Roads are direct in their direction from one point to another, and this aspect can be seen over some rather long distances, but a closer view of the Roman Road clearly shows that the road, as laid down, is a series of sections, each just a few kilometres in length, which are laid from specific point to specific point, while still following an overall direct route. These “sections” suggest a unique way of determining the road-line moving in a direct way toward a distant goal, while considering the geographically important points along the road-line. At this time just how the Roman Surveyors determined the obvious Road Line is still very much a mystery: the real problem arises when it becomes necessary to lay out a road-line in country which is heavily wooded, or which is hilly between the departure points mentioned above and is therefore invisible from on point to another. It would seem that the determination of the road-line was accomplished in different stages, each necessary for the final determination of the building line. The first may well have been the use of elevated beacons probably at either dawn or dusk to establish the primary alignment of the road-line. The second part of the road-line establishment would be a ground survey to determine the best route around obstacles at close intevals with stakes or marker stones. In areas where a wide river estuary or unusually difficult ground was found between primary stations, the primary route could be changed to determine a more reasonable route that would be easier to build upon.
How a Roman road was built
The natural obstacles were usually crossed with embankments and bridges. The groma was the main tool which the agrimensor used to trace a straight line on the ground. The tool is constituted by two arm fixed with a pivot to support them vertically. At the end of each of two arms a lead thread was hung up. His helper was at a certain distance with a peg and planted it in the ground according to the indications of the surveyor (or gromaticus), giving indications thanks to the arm of the groma. In Rome, the agrimensores, or gromatici, were a category of free professionals that enjoyed a large consideration. After having carried out all the measurings, a pit was dug, normally not larger than five meters; this was replenished with layers of statumen (stone) to form the paving of the bottom; then another smaller layer of stones with rudus (malt) was layed; then an intermediate layer of gravel mixed with sand or gravel (nucleus) on which leaned the external covering. The paved floor (agger or pavimentum) was formed by huge stones called basoli and layed to ease the drain of water to the borders of the road called margines or crepidines (from crepidae: sandals). The word road derives from stratum (paved) the system that allows to distinguish the Roman road from the dusty tracks of the antiquity.
The milestones
During the journey the distance to get the goal was indicated by columns of stone, at regular intervals, standing at the edges of the road. On them it was carved the indication of the builder and the distance from Rome or the other important cities of the empire; it came in MP (milia passum, which corresponds about mts 1478). The beginning of the distance was calculated not from the city centre but from the gates of the walls. This also happened in Rome where, even if the Miliarum Aureum in the forum indicated the distance from some cities of the empire, the distance was still calculated from the gates in the Servian walls.
The milestones’ shape was a sort of cylinder to allow the traveller to read the indications without the need to stop the cart or the horse. The Cursus Publicus (the road network) expected every 10 miles a statio and every 30 miles a mansio. Roads had a general width of 14 foot = 4,2 mts.
References:
“Modulo didattico multidisciplinare”, Silvia Fioretti
“The Penguin Historical Atlas of Ancient Rome”, Chris Scarre
“Toponomastica”, Salvatore Arca, I.G.M., Firenze
website www.aritaly.net, Alessandro Razze