Vellaunus is a Celtic god

Celtic polytheism

Celtic polytheism, commonly known as Celtic paganism, refers to the religious beliefs and practices adhered to by the Iron Age peoples of Western Europe now known as the Celts, roughly between 500 BCE and 500 CE, spanning the La Tène period and the Roman era, and in the case of the Insular Celts...

 known from only two inscriptions. The first, found at Caerwent

Caerwent

Caerwent is a village and community in Monmouthshire, Wales. It is located about five miles west of Chepstow and eleven miles east of Newport, and was founded by the Romans as the market town of Venta Silurum, an important settlement of the Brythonic Silures tribe. The modern village is built...

 is the base of a state recording the dedication of the statue to:

[DEO] MARTI LENO

[S]IVE OCELO VELLAVN ET NVM AVG

M NONIVS ROMANVS OB

IMMVNITATEM COLLEGNI

D D S D

GLABRIONE ET H[OM]VLO COS D X K SEPT

"To the god Mars

Mars (mythology)

Mars was the Roman god of war and also an agricultural guardian, a combination characteristic of early Rome. He was second in importance only to Jupiter, and he was the most prominent of the military gods worshipped by the Roman legions...

 Lenus

Lenus

Lenus was a Celtic healing god worshipped mainly in eastern Gaul, where he was almost always identified with the Roman god Mars. He was an important god of the Treveri tribe, who had large sanctuaries at medicinal springs at Trier and the Martberg by Pommern in what is now Germany. Two dedications...

, otherwise known as Ocelus

Ocelus

Ocelus is a Celtic god known from three inscriptions in Roman Britain. He is twice invoked on dedications at Caerwent: one stone is the base of a state of which only a pair of human feet and a pair of goose feet survive. The invocation is to Mars Lenus or Ocelus Vellaunus and the "numen" of the...

 Vellaunus, and to the Imperial numen, M. Nonius Romanus, by privilege of the college, dedicated this gift using his own funds during the consulship of Glabrio and Homulo ten days before the kalends of September."

Above this base there survives only a pair of human feet and those of a goose. The dedication dates to AD 152.

Mars Lenus was a god of the Treveri

Treveri

The Treveri or Treviri were a tribe of Gauls who inhabited the lower valley of the Moselle from around 150 BCE, at the latest, until their eventual absorption into the Franks...

 with great cult centres at Trier

Trier

Trier, historically called in English Treves is a city in Germany on the banks of the Moselle. It is the oldest city in Germany, founded in or before 16 BC....

 and Pommern; Ocelus was a local British deity, to whom another stone was inscribed at Caerwent, and who was also worshipped at Carlisle. Mars Lenus was clearly equated in Britain with other, localised Celtic divinities.

The second inscription dedicated to Vellaunus was located at Hières-sur-Amby

Hières-sur-Amby

Hières-sur-Amby is a commune in the Isère department in south-eastern France.-See also:*Communes of the Isère department...

 in the territory of the Allobroges

Allobroges

The Allobroges were a Celtic tribe of ancient Gaul, located between the Rhône River and the Lake of Geneva in what later became Savoy, Dauphiné, and Vivarais. Their cities were in the areas of modern-day Annecy, Chambéry and Grenoble, the modern of Isère, and modern Switzerland...

 in southern Gaul. It reads:

AVG SACR DEO

MERCVRIO

VICTORI MAC

NIACO VEILAVNO

C CAPITOIVS MACRI

NVS RESTITVIT

"To Augustus and the 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...

 the Victor Macniacus Vellaunus, C. Capitojus Macrinus restored this sacred object."

Here Vellaunus occurs as one of several epithets of Mercury.

The root uellauno- is found in many other Celtic names, including those of the goddess Icovellauna

Icovellauna

Icovellauna was a Celtic goddess worshipped in Gaul. Her places of worship included an octagonal temple at Le Sablon in Metz, originally built over a spring, from which five inscriptions dedicated to her have been recovered; and Trier, where Icovellauna was honoured in an inscription in the...

; the hero Cassivellaunos

Cassivellaunus

Cassivellaunus was an historical British chieftain who led the defence against Julius Caesar's second expedition to Britain in 54 BC. The first British person whose name is recorded, Cassivellaunus led an alliance of tribes against Roman forces, but eventually surrendered after his location was...

, later famous in Welsh legend as Caswallawn; and the Catuvellauni

Catuvellauni

The Catuvellauni were a tribe or state of south-eastern Britain before the Roman conquest.The fortunes of the Catuvellauni and their kings before the conquest can be traced through numismatic evidence and scattered references in classical histories. They are mentioned by Dio Cassius, who implies...

, a tribe of southeastern Britain, whose name may also be cognate with Catalauni (Châlons-sur-Marne) and Catalaunia (Catalonia

Catalonia

Catalonia is an autonomous community in northeastern Spain, with the official status of a "nationality" of Spain. Catalonia comprises four provinces: Barcelona, Girona, Lleida, and Tarragona. Its capital and largest city is Barcelona. Catalonia covers an area of 32,114 km² and has an...

). The meaning of uellauno- has been variously interpreted. It has been glossed by Pierre-Henri Billy as "bon" (good); however, P.-Y. Lambert derives it from *uelna-mon-, meaning "chef, commandant, dirigeant" (chief, commander, leader). The latter derivation has been accepted as definitive by Xavier Delmarre and accords well with the Latin epithet victor found alongside vellaunus in the Hières inscription.