‘Natural’ loci such as woods, groves and trees are often advanced as Celtic cult loci par excellence (Henig 1984: 17; Green 1986: 19-22), This concept of Celtic sacred space derives in part from classical texts, but references on this theme do not commence before the first century AD (e. g. Mela, Chorographia III.2.18; Lucan, Pharsalia 1.451-8, III.339-425; and Pliny Natural History XVI.103-4), when woodland sites are frequently associated with the druids. Iron age references to ‘natural’ loci are rare. In c. ioo BC Artemidorus commented on a open-air ritual at Cape St Vincent in western Spain (Strabo III.1.4), and Poseidonios on the use of lakes as sacred repositories in the Toulouse area of the Provincia (Strabo IV.1.13). Strabo also stated that the Celtiberians worshipped a nameless god outside their houses (ill.4.16). Although only Artemidorus makes explicit reference to the absence of structures, all three texts may imply rituals without use of formal (roofed) structures, or otherwise involving the restructuring of space; for example by construction of an enclosure. There are no other iron age references to such ‘natural’ cult sites.
The first-century AD change in emphasis to woodland sites is ignored by archaeological commentators except Wait (1985: 204), although we can advance reasons for a change in practice at this point. Imperial proscription of the druids could have forced the use of secluded locales. Equally, as Chadwick noted (1966; 38), the textual association of druids and groves could be the result of a spurious etymology, voiced in Pliny’s suggestion (xvi.249) that ‘druid’ derives from the Greek word for oak (dptiq). It is not impossible that the association of groves with Celtic religion is a literary construct of the first century AD.
The concept of nature-based Celtic religion is also predicated on the apparent paucity of archaeological evidence for tectonic loci. As such sites would leave little archaeological trace, this proposition remains difficult to test, but it is important to note that the archaeological record is likely to be biased in favour of formal structures. Bearing this in mind, what evidence can be adduced for ‘natural’ loci?
Nemeton
Nemeton is a Celtic descriptor for sites of cult significance. Aside from one textual reference (Strabo Xill.5.1 on the Galatian Drunemeton), nemeton is attested mainly in post-conquest place-names and epigraphy, over a wide area. Place-names include Augustonemetum (Clermont-Ferrand) and Nemetodorum (Nanterre) in Gaul, Nemetobriga (near Ortense) in Spain, and Medionemeton (near the Antonine Wall) in Britain. Epigraphic attestations include Mars Rigonemetis from Britain (Nettleham, Lines.) and Nemetona from Altripp (Spier).
Nemeton is commonly glossed ‘sacred grove’ (Green 1986: 111-12; Webster 1986; 107), with little indication that it principally denoted such sites. Rather, as Rivet and Smith suggest (1979: 254-5), nemeton had several meanings, including grove or clearing (Piggott 1968; 71-2) and small shrine or chapel (cf. the Irish nemed, glossed sacellum, suggestive of a small shrine). Formal structural associations are a possibility for some examples, as at Vaison-la-Romaine (Vaucluse, France; see Goudineau 1991: 252), where an inscription records the dedication of a nemeton to Belissama.
Goudineau’s suggestion that this nemeton was a grove is unlikely, and the context suggests a structure or precinct. Nemeton thus remains enigmatic. The most acceptable gloss, MacCana’s ‘a sacred place’ (1983: 14), simply emphasizes how little we may infer from the term regarding the form of Celtic cult sites.