The linguistic prehistory of an area can be illustrated by its place names. For example, within the borders of present day France we find place names that reflect Gaulish, Latin, Frankish, German, Breton and Basque linguistic material, eventhough people in France nowadays primarily speak French. Place names are also interesting because of the cultural information they may contain. The fact that the French town Beaulne contains the name of the Gaulish god Belenos may indicate that historically a shrine to that god was situated there, eventhough no archeological research has been able to locate such a shrine. Because people do not quickly change the name of a locality the fossilized lexical material that a toponym contains provides a valuable window on prehistoric society.
When do people change the name of a locality? When invading peoples take possession of a locality they may want to affirm its new identity by renaming it. For example, most place names in the Netherlands clearly have Germanic origins eventhough some places were inhabited long before the Germanic speaking peoples arrived. On the other hand, invading peoples may also choose to continue the old names. The cities of Northern France generally have retained their Latin names eventhough the Germanic speaking Franks took possesion of them in the late 5th century. The villages on the countryside however got Frankish names. Therefore the distribution of Frankish toponyms in Gaul informs us about the reach and nature of the Frankish conquest. Sometimes invading peoples reinterpret the name of a locality according to their own language. For example, when the Franks conquered the Gallo-Roman town Turnacum (Gallo-Romance *tornako) they interpreted it as containing their native word *þurn meaning “thorn,” which is why the place is now known as Doornik (Gysseling 1960: 973). Sometimes a place name is changed in order to counteract its association with pagan religion. This seems to have been the case with the Medieval German place name Wuodenesberg (modern day Bad Godesberg) which means “the mountain of Wodan.” In the highly Middle Ages the clergy quite activily turned the initial w w into a g in order to associate the place with the christian god instead of pagan Wodan (Quak 2002: 59).
Sometimes a place was known by multiple names. The Dutch city of Utrecht was known in the Early Middle Ages by both its Frisian name Wiltanaburg (the borough of the Wilts, presumably a local clan) and its Latin name Trajectum. The Latin name evolved into Romance *trajecto before the onset of the Middle Ages and was pronounced as *trajiχt by the Pre-Frisian population. Pre-Frisian *trajiχt underwent umlaut to *trejiχt and was subsequently shortened to *treχt which is the name we find written in 9th c. diplomas as Treht (Gysseling 1960: 989). In this case it is clear the Latin name was more succesful than the Germanic name, which may have to do with the fact that Utrecht became a bishopsee in the early 8th century and the church preferred the Latin name above the Frisian name.
However, this blogpost mainly concerns French toponyms and more precisely place names referring to Roman deities. When the Romans conquered Gaul half way the first century BCE they initiated a long proces of Romanization. Romanization can be understood in many ways and presumably differed from region to region but generally we can regard it as entailing an appropriation and adaptation of Roman modes of expression by local communities. For example, the Roman army and administrators brought along their Roman religion when they settled in Gaul. In their Roman style cities they built Roman style temples for their Roman gods. These temples were roughly the same all over the Roman Empire, namely the podium style rectangular temple with the columnade before the entrance. The Gauls however adapted the Roman building style to their own tastes. Presumably because of the shape and nature of indigenous Gaulish harrows quickly a Gallo-Roman type of temple complex emerged, build from stone with columns all around, usually also rectangular but sometimes also in round or diagonal shape (Dowden 2000: 130). Some of the Roman gods were also adopted by the Gauls and sometimes equated with similar deities from their own pantheon. For example, the Roman god Mercurius apparently ressembled the Gaulish god Vellaunos which led to a merger of the two deities. The god was then referred to by two names, the Roman one and the Gaulish one. On a wall of a Roman cemetery in Hières-sur-Amby we find an inscription to DEO MERCURIO VICTORI MAGNIACO VEILAUNO “to the god Mercury, the great victor Veilaunos” (Marichal et Mirot 1920: 114).
But Gaulish and Roman paganism did not last. In the second and third centuries CE christianity spread over the Roman empire and quickly supplanted the local religions. The fact that we still have French place names naming Roman gods despite the change in religion from paganism to christianity is odd to say the least. Late Antique and Early Medieval christianity is known for many things but tolerance is not one of them. The names of Gaulish gods may have been forgotten when christianity spread over the Gallo-Roman countryside but the names of the Roman gods never fell into oblivion. They were well known by the clergy because classical writings were full of them and reading Virgil was part of every monk’s core curriculum. Apparantly the communities did not feel the need to change the name of their locality when they switched religion. It is unclear how much the church would have bothered about the pagan names of certain localities. In some cases we know a pagan name was substituted by a christian one. A prime example is the Montmartre which was earlier known as the mons mercurii. The name would have evolved into Gallo-Rom. *mɔntmɛrtre which was changed into *mɔntmartro which meant “the mountain of martyrs.” But apparantly in many cases the pagan names, despite being recognizably pagan, were no subject of clerical concern.
North against South
We might also wonder why place names referring to Roman gods are predominantly located in the south of Gaul. Partly this may reflect the fact that the south of Gaul was more urbanized, more densely populated and more Romanized than the north of Gaul. Also we should note that almost all the theophoric toponyms are small localities. Since the religious topography to administer the small parishes was absent in much of the Early Middle Ages it is possible some places remained just outside the scope of a criticizing clerical eye. Additionally, the North of Gaul had suffered greatly under the imperial crises of the 3d century and many villae were abandoned. Presumably many settlements disappeared in this period and much of the countryside was only resettled a few centuries later by predominantly Frankish colonists. This may also have caused some earlier Gallo-Romance place names referring to Roman gods to disappear without a trace.
We may note that most of the sacral place names in the North of Gaul refer to the wargod Mars. This is to be expected because of the more martial and less urbanized society of northern Gaul. We should note that the North of Gaul often fell prey to incursions of barbarians. Therefore the military presence was considerably higher in the North than in the South. Also, most northern settlements predominantly depended on animal husbandry for maintenance. Since Jupiter and Mercurius were mainly “urban” gods tending to “urban” needs, worshipping a martial wargod makes more sense for these agrarian societies.
The only place name in the north of Gaul that could possibly refer to Jupiter is Jeumont, close to the Belgian border (Carnoy 1917: 168). It seems unlikely that this place name is really derived from Rom. *ʤɔβemɔnte << Lat. jovis montem. In Gallo-Rom. the synthetic genitive was lost because of the restructuring of the vowel system and subsequent restructuring of the case system. In Gallo-Romance, as is clear from the syntax of the Lex Salica, genitival relations were mainly expressed by way of the preposition de + oblique, e.g. Lex Salica aliqui de ipsos “several of them” and tres de eo contubernio “three of that gefolgschaft”. A trace of the synthetic genitive lived on in appositional genitive constructions were a head noun and dependent noun in the oblique followed eachother, e.g. Lex Salica consilio domine “the advice of the lord” and ventre matre “the belly of the mother.” We also find traces of this constructions in Modern French, e.g. ModFr. fête-dieu and Bain-Marie. Since in toponyms the theonym regularly follows the first element it seems unlikely that jeumont would be an exception. Especially since we have montjoux < *mɔnteʤɔβes and fanjeaux < *fanoʤɔβes attested. A more likely scenario would be that Jeumont derives from Latin jugum montis “the ridge of the mountain,” i.e. > Lat. jugum montis >> Rom. *ʤoγomɔnte > ModFr. Jeumont.
On a final note I’d like to draw attention to the only Frankish toponym on the map, namely ModFr. Aulers in the name Bassoles-Aulers (Quak 2002: 61). This place name contains the name of the pagan gods which are known in Old Icelandic as Ásir or in Old English as Esas. i.e. Old Frankish *ansu-. As a onomastic element this lexeme became fossilized in names such as Oswald, Oswin and in Dutch in the place name Oegstgeest < *ōsgāresgēst “the barren grounds of Osger.” The French place name Aulers seems to continue this element *ansu- referring to the pagan deities in combination with the element *hlǣri (cf. ModDu. –laar), i.e. Old Frankish *ansu + *hlǣri > ModFr. aulers (1017 anslari). This toponym proves that at the time of the Frankish colonization (5th and 6th c. CE) at least some Frankish groups still adhered to their pagan religion. This lends credibility to the missionary tales of the Merovingian period in which it is told Northern Gaul needed to be rechristianized after the Age of Migrations.
Canoy, Albert J., “Adjectival Nouns in Vulgar LAtin and Early Romance” Romanic Review 8 (1917).
Dowden, Ken, European Paganism; realities of cult from antiquity to the Middle Ages (New York 2000).
Gysseling, Maurits, Toponymisch Woordenboek van België, Nederland, Luxemburg, Noord-Frankrijk en West-Duitsland (vóór 1226) (1960).
Marichal, Paul et Leon Mirot, Les noms de lieu de France; leur origin, leur signification, leur transformation (Paris 1911).
Quak Arend, “Germaanse sacrale plaatsnamen in de Nederlanden” Naamkunde 34 (2002).
 The rounding of the *a before nasals is a specific Northsea Germanic development shared by English, Frisian and some of the coastal dialects of Middle Dutch.