right|300px|thumb|An altar to Mars Loucetios at The Rhine in the [[Musée archéologique (Strasbourg)|Musée archéologique de Strasbourg.]]
In Gallo-Roman religion, Loucetios (Latinized as Leucetius) was a Gallic god known from the Rhine-Moselle region, where he was identified with the Roman Mars. Mars Loucetius was worshipped alongside the goddess Nemetona.
Name and etymology
The name Loucetios derives from a Celtic stem *lowk-et-, meaning 'flash of lightning, thunderbolt' (cf. Old Irich lóchet), itself from the root *lowk- ('bright, light'; cf. Middle Irish luach 'glowing light', Middle Welsh llug 'eyesight, perception'). It is the source of the place name Luzech, attested as Luzechium in 1326 CE.
The name may be a reference to either a Celtic common metaphor for battles as thunderstorms (cf. Old Irish torannchless, the 'thunder feat'), or else the divine aura of the hero (the lúan of Cú Chulainn). It is presumably analogous to Oscan Loucetius ‘light-bringer’, an epithet of Jupiter.
Inscriptions and shrines
About a dozen inscriptions in honour of Mars Loucetius have been recovered, mainly from eastern Gaul, with a particular concentration among the Vangiones and Aresaces (two Rhenish tribes). Inscriptions to him have also been found at Bath and Angers; the altar at Bath specifies that it was dedicated by a citizen of the Treveri.
Inscriptions often invoke Mars Loucetius together with Victoria or Nemetona). Edith Mary Wightman considers this pair “closely similar to if not identical with, Lenus and Ancamna”, ‘in honour of the divine house’ (i.e. the imperial family).
Wightman further suggests that the shrine of Mars Loucetius at Klein-Winternheim, south of Mainz, was “a central one for the Aresaces”,