Artaius is a Celt

Celt

The Celts were a diverse group of tribal societies in Iron Age and Roman-era Europe who spoke Celtic languages.The earliest archaeological culture commonly accepted as Celtic, or rather Proto-Celtic, was the central European Hallstatt culture , named for the rich grave finds in Hallstatt, Austria....

ic epithet applied to the Roman god Mercury

Mercury (mythology)

Mercury was a messenger who wore winged sandals, and a god of trade, the son of Maia Maiestas and Jupiter in Roman mythology. His name is related to the Latin word merx , mercari , and merces...

 during the Romano-Celtic

Gallo-Roman religion

Gallo-Roman religion was a fusion of the traditional religious practices of the Gauls, who were originally Celtic speakers, and the Roman and Hellenistic religions introduced to the region under Roman Imperial rule. It was the result of selective acculturation....

 period. It is known from a single inscription from Beaucroissant

Beaucroissant

Beaucroissant is a commune in the Isère department in south-eastern France....

 in the Isère

Isère

Isère is a department in the Rhône-Alpes region in the east of France named after the river Isère.- History :Isère is one of the original 83 departments created during the French Revolution on March 4, 1790. It was created from part of the former province of Dauphiné...

:

MERCVRIO

AVG ARTAIO

SACR

SEX GEMINIVS

CVPITVS

EX VOTO

"To the august Mercury Artaius, Sextus Geminius Cupitus (has dedicated this) sacred (stone) in fulfillment of a vow

Ex-voto

An ex-voto is a votive offering to a saint or divinity. It is given in fulfillment of a vow or in gratitude or devotion...

."

In Gaulish

Gaulish language

The Gaulish language is an extinct Celtic language that was spoken by the Gauls, a people who inhabited the region known as Gaul from the Iron Age through the Roman period...

, the word artos means ‘bear’, and artaios would have been a derivative (meaning something like ‘ursine’). Miranda Green

Miranda Green

Miranda Jane Aldhouse-Green FSA is a British archaeologist, who is Professor of Archaeology at Cardiff University....

 considers Mercury Artaius to have been a bear-god

Bear worship

Bear worship is the religious practice of the worshiping of bears found in many North American and North Eurasian ethnic circumpolar religions such as the Sami, Nivkh, Ainu, and pre-Christian Finns...

. It is also possible that Artaius is derived from a place name (so that, as an "Artaian Mercury", he would only indirectly have any association with bears - if at all) - the inscription above was discovered at a location that was once called Artay and there is a similarly named town, Artaix

Artaix

Artaix is a commune in the Saône-et-Loire department in Bourgogne in eastern France.-References:*...

, in Saône-et-Loire.