Julius Caesar is probably the most famous Roman of all. As dictator, he paved the way for the establishment of the Roman Empire under his great-nephew Augustus, more infamously, had a love affair with Cleopatra of Egypt, and even invented the leap year, before being assassinated by friends and colleagues who had previously supported him. But before his dictatorship he had conquered a vast area of Europe in an incredibly short time. Caesar’s Gallic War is the most detailed eye-witness account of war that survives from the Greek or Roman world.
In Book I, chapter 5 of his Gallic War, Julius Caesar writes of the Helvetii’s practice of migrating en masse and of burning down their oppida or walled towns, villages and houses as they went. This would certainly explain the lack of remains of urban construction and monuments, and is likely to have been common to the Celts as a whole.
Evidence of the existence of oppida or walled settlements has been found in the Cisalpine area and elsewhere and date to the third and second centuries B. C. Among the most prominent surviving monuments in continental Europe of the late Celtic period are the oppida (sing. ppidum) or large fortified settlements that have an urban character. They were constructed on naturally protected sites, and some remains of the massive original perimeter walls have turned up in Gaul and on the right bank of the Rhine, as well as in Danubia. Together with the rectangular enclosures (Viereckschanzen) that were probably part of the nemeta or open-air sanctuaries created by the rural population, the oppida are the most significant group of monuments surviving from this time (Jimene 90).
The first surveys were made by Baron Stoffel, an officer under Napoleon III, who embarked on a series of historical investigations into the sites of Julius Caesar’s battles in Gaul. Since then, knowledge has been based on excavations carried out in the west and east, on the careful assessment of material unearthed, and on the new and painstaking historiographical and philological interpretations of Caesar’s chronicles of his campaign in Gaul, Gallic War.
The derivation of the concept of oppidum from Caesar’s war campaign chronicles and the progressive extension of its application as archaeological research proceeds make it necessary to explain exactly what is meant by the term oppidum in its more restricted sense. Caesar divides the settlements of Gaul into three categories: oppida (fortified towns), vici (villages) and aedificia or aedificia privata (single farmsteads).
This careful subdivision not only gives a clear indication of the different types of settlement pattern, increasingly confirmed by the present-day archaeological campaigns, but also gives an idea of the function of the oppida. Even with their large populations, the oppida cannot have been entirely selfsufficient. To some extent at least, they also served as storage points for crops and livestock, as well as centers for the processing of raw materials to cater for both town and countryside.
As a result of this they also functioned as marketplaces, especially once regular coinage came into use in the second century B. C. , when coins of base metals (bronze or those known as potins), and in small denominations, made their appearance. The term urbs is used sparingly in Caesar’s account to highlight the importance of a handful of larger locations, such as Alesia, Gergovia and Avaricum. Unlike the oppida of free Gaul, the towns of Tolosa ( Toulouse), Narbo (Narbonne) and Vienna, situated in the Provincia, were subject to provincial Roman administration, as implied by their definition as civitates.
Caesar also uses this expression to define ethnic communities in Gaul in terms of political and administrative entities. The central role of the oppida in the political, economic and cultural life of the Gaulish groups (and hence their strategic importance as fortified outposts for the Roman armies), is clearly described in Caesar Gallic War, which lists the oppida of twenty-nine different Gaulish tribes, with their names followed by a brief description.
Some tribes, however, had control over more than one town (twelve in the case of the Helvetii). But most of the population of the time was scattered through villages and farmsteads. As for southern Germany, the diffusion of nemeta – rectangular enclosures that were presumably nature sanctuaries for the rural populations – and the proliferation of sites containing graphite-decorated pottery indicate a significant population in the countryside outside and between the large oppida (Zander 2005).
Furthermore, over a wide geographical area numerous unfortified settlements in advantageous trading sites have yielded considerable information on the metal and pottery workshops. Some of these sites could be classed as trading posts. Their position along the navigable waterways, at harbors or fords seems to have been decisive in their development. In addition to the civitates or capitals of the separate races, there were also smaller urban-type settlements, presumably the centers of small territories, such as a pagus.
It is reasonable to assume that not all these centers were founded at the same time. The location, size and, presumably, the number of inhabitants, varies depending on the political and economic importance of the settlement. Despite their many common features, settlement types are not consistent. Although the information offered by Caesar is sound only where the territories of his military campaigns are concerned, certain basic urban features he mentions have a more general application, as corroborated by archaeological research undertaken in the larger fortified settlements.
This is valid if we consider the term oppidum in its broadest sense, that is, an urban settlement with a sizable population, which is both regional center and refuge for smaller settlements and populations over a wide area. None of the definitions that in each case highlight some specific feature can claim to be generally applicable to all late Celtic fortifications.
The reason for this lies not so much in Caesar’s choice of term (which is limited to the campaign in Gaul) or in the variability of his meanings, as in the insufficient development of archaeological research. The details of site position and outward appearance could not be described more accurately than Caesar did in his account of the oppidum of the Sotiates tribe: oppidum et natura loci et manu munitum (“a fortified town in a natural location and built by the hand of man,” Gallic War, III, 23). For all this, Caesar’s memoirs are still a lively and informative resource.