Thursday, October 30, 2014

His aqueducts and his cartography:
Frontinus, Roman law and the missing maps of the waters of Rome

The foundations of the science of land measurement lies in practical experience, since the truth about sites or area cannot be expressed without lines that can be geometrically measured.

                                                                                                   --Frontinus, De arte mensoria

According to R.H.Rodgers, 'obscurity veils the early career of Julius Frontinus,' who in the year 97 was appointed curator aquarum of the city of Rome. Frontinus wrote two groups of texts that are important to us here in our study of Roman cartography; those being De Aquaeductu urbis Romae and a series of texts on Roman surveying. The work that remains extant on Roman surveying is found in the Corpus Agrimensorum and is very fragmentary. Karl Lachmann (shown below), who worked on the first edited edition of the text, believed that the full work comprised two books, the first consisting of De Agrorum Qualitate and De Controversiis, the second work containing De Limitibus, De arte Mensoria and some other more fragmentary texts from Urbicus, another writer on Roman surveying who may have copied his work from the now missing parts of Frontinus.

Besides his interest land surveying however, Frontinus is more well-known for his text on the aqueducts of Rome. (For more on this see the website run by Katherine Rinne) In the text of De Aquaeductu urbis Romae he discusses the fact that he made maps used in the administration of the aqueducts. In the prologue to the book Frontinus refers to his work as a commentarius, and explains that it is a collection of data and other materials that he made primary for 'himself'. The contents of the book are quite technical and numerical, pertaining to sizes of individual aqueducts, the dates they were built, pipes and their sizes, the quantities of water delivered and legal matters relating to the right of private individuals to the use of public water. Although most of the material serves an adminstrative aim some of the text deals with methodological issues and it is these that are of interest for historians of cartography. In Chapter 17 of his book on aqueducts Frontinus writes:

Non alienum mihi visum est longitudines quoque rivorum cuiusque ductus etiam per species operum complecti. nam cum maxima huius officii pars in tutela eorum sit, scire praeposiutum oportet quae maiora impendia exigant. nostrae quidem sollicitudini non sufficit singula oculis subiecisse; formas quoque ductuum facere curavimus ex quibus adpareret ubi valles quantaeque, ubi flumina traicerentur, ubi montium lateribus specus adpliciti maiorem adsiduamque petendi ac muniendi vi exigerent curam[1].

Which translates as:

It has seemed to me not unfitting to include as well as description of the lengths and courses of each aqueduct, according to the classifications of construction. Because the greatest part of the duties of this position lies in the maintenance of the lines, the man in charge must know what thongs demand greater outlays. My sense of responsibility has not been satified with personal examination of particular items. I have also taken care to prepare maps of the lines, from which it is clear where there are valleys and how great they are, where rivers are crossed, and where channels attached to the sides of mountains demand greater and constant attention...for their repair.

Hence we learn here that Frontinus had detailed maps made of the aqueducts describing not only the lines themselves but also the topography of the surrounding countryside that they traversed. According to Harry B. Evans, in his Water Distributon in Ancient Rome, (Michigan, 1994), "Frontinus' mapmaking merits closer attention." Evans postulates that Frontinus' data, which he gives in the text on aqueducts, is in fact derived from the maps that he had made and that those sections of the text describing the actual lines are commentaries on the maps themselves. There are other indications in the text that Frontinus is using maps as he pinpoints some of the sources of the aqueducts by using exact spatial references to the existing road system outside of Rome.

  Although none of Frontinus maps survive there are maps on inscriptions that show what aqueducts maps may have looked like. An example shown here (CIL 6.1261) displays in graphic form the lines of an aqueduct and the epigraphy gives indications of water flow and on what legal terms individuals may draw water from particular lines. The inscription contains the names of the people who shared the channel that came off the aqueduct, the volume of water that they where alloted, and the scheduled times that they could take that allotment.

The inscriptions translates as:

a. for Thyrsis, freedman of Augustus, two pipes from the second to
the...hour, on the fourth day before.. 
b. for the freedman of C. Julius
Caeser, C. Bicoleus Rufus Squaterianus, one pipe... 
c. to the Aufidianum of Julius Hymetus, two pipes from the second
to the sixth hour... 
d. To Vibius...pipes, to C. Bicoleus, Freedman of C. Julius
Caesar,... pipes from the sixth hour until sunset...

There are several known examples of this type of inscription and another is shown below (CIL 14.3676). This inscription describes a shared channel related to the supply of water at Tibur, a rural area outside Rome. The stone containing the inscription is found built into the side of the Church of Saint Peter at Tivoli and it preserves a fragment of a map showing two channels. The inscription itself lists the people to whom the water is to go to, the amount of water they have been alloted, and the time of day when it may be taken. (for more on water rights see Cynthia Jordan Bannon, Gardens and Neighbors: Private Water Rights in Roman Italy, Michigan, 2009). As Evans says, all of this deserves further work....and can help us understand some of the lesser known aspects of Roman cartography and its application.

Of all those who have studied the topography of Rome and its ancient aqueducts perhaps the most important was Thomas Ashby who surveyed their extant remains in in Rome and its outskirts for many years at the beginning of the 20th century. Ashby's work, published after his death by his wife will never be improved upon since many of the ruins he examined have long since disappeared.

Many of Ashby's notebook still survive and his photographs and drawings are an unparalleled resource any scholar interested in these great Roman constructions.

[1] I have used the new edition of Frontinus by R.H. Rodgers, "De Aquaeductu urbis romae", Cambridge Classical Texts and Commentaries 42, 2004.