As Celtic people conquered by the Romans adapted their religion to that of the Empire’s, I have begun using the Roman calender as a guide for when to honor Celtic deities. There’s no real way to make direct correlation between the two pantheons; Celtic Gods tend to be tribal hero kings (and possibly first ancestors) who are great at everything, and Celtic Goddesses often hold power over the fertility and death of the tribe’s land, water, livestock and human members, especially the king. However, to unify the Empire, other peoples’ deities were called by Roman names much like the Greeks once did. It’s now thought that the Celts had more power in deciding what Roman deity to choose than formerly believed. The Celts transformed aspects of Roman religion to fit their own cosmology and over the course of a few generations new versions of Celtic religion appeared.
Whether or not any Celtic people worshiped their tribal deities on dates of Roman Festivals then, Celtic polytheism is still adapting. Most Celts would have known the deities of their tribe and (if in one) their larger federation. These were personal, connected to place and ancestry, and a large part of one’s identity. Today we don’t know a lot about the majority of Celtic deities (although we have over 400 names), but most modern Celtic polytheists have their own pantheons of a larger geographical region and period of time. Even a Gaelic polytheist worshiping the Tuatha De Danann is doing something quite modern, as tribes worshiped the deities of their territory of Ireland. It was one way tribes in power stayed in power, until big changes in the ruling tribes led to adopting Saints to justify their new power.
The Roman calendar is an easy way to plan rituals for those Gaulish, Iberian and Brythonic deities who were matched with a Roman deity. I began this with the most popular Celtic God most people have never heard of, Telesphorus; then Lenus, Neto, Rudianos, Cocidius, and Nemetona March 1st; and last month Ataegina and Erecura. The only Celtic deity known to have His own Celtic Festival is Erudinus of northern Spain, but I have found matches for Ogma and Ogmios, the smith deities and the “native” Venus, Sirona, Sulis, Andraste, Brigantia, Grannus, Abnoba and the Celtic understanding of Diana.
On May 15, or the full moon of May, Roman merchants honored the God Mercury with the Mercuralia festival. An interesting thing about Mercury is that the Gauls worshiped Him even more ardently than the Romans. He was easily one of the most popular, if not the most popular, deities in Gaul. He was sometimes associated with a Celtic God, but in general the Gauls embraced Him as Himself.
There are records of Gaulish merchants hiring Roman artisans to make large statues of Mercury. It may be that these merchants brought the cult to their own communities. How Mercury was understood and worshiped at this time would have probably been a very Gaulish way. Some knowledge of the God didn’t mean that the merchant had a great wealth of information about Roman religious practices or mythology. Mercury was most likely growing into a Gallic deity while around them the world of the Gauls grew more Roman. Gaul was thriving with import-export business, and tribes who controlled major rivers were in a powerful position. Trade with Britain was not new, as goods crossed the Channel to and from southeast England to the Rhine River. The Romans built cities like London and their famous roads which made markets and transportation to other parts of Britain (including troops stationed at Hadrian’s Wall) much easier. One reason why Julius Caesar was so eager to conquer Gaul was to get their precious metal mines. Celtic fabric quickly became popular in Rome.
Mercury as the God of not only commerce but also transportation, was the backbone of the strength of Gaul. Yet, to the Romans, He was generally viewed as primarily the messenger of the deities.
Most scholars associate Mercury with Lug/ Lugus, who was widely worshiped by many Celtic peoples: the Celtiberians, the Luggones of Spain, the Gauls, the Gaels, and the Britons. Lug and Odin seem to have an ancient connection, going back perhaps 4,000 years to a group of Indo-European people possibly in or near the Czech Republic who would later become the Germans and the Celts. Currently, archeological evidence of Bronze Age Scandinavia and Celtic Iberia and the Celto-Germanic language is being studied by scholars such as John T Koch to prove the ancient shared roots.
Linguistically the two Gods have quite a lot in common at this point from the spear to having or closing one eye. Also Lug’s mythology from Ireland and Wales (as Lugh and Lleu) has strong connections with myths about Odin. (Steel Bars, Sacred Waters has more in depth information.)
Starting with Lugus (pronounced “LOO-guss”), His companion Rosmerta and another Celtic deity associated with Mercury named Cissonius (pronounced: kiss-SOH-nee-us) the carriage driver are described. As we don’t have much information about the Mercuralia, use your imagination while working with knowledge of Celtic ritual.
From Steel Bars, Sacred Waters:
“Lugus was worshiped by the Gauls but rarely by that name. When first describing the deities of the Gauls, Julius Caesar wrote in De Bello Gallico that the Roman God Mercury was their most important God. (When the Romans wrote about other peoples’ deities they used the names of the Roman ones that best matched the local deities. It helped hold a multicultural society together.) Important Lugus became so strongly associated with the Roman God Mercury that Mercury actually did become the most popular deity for the Roman Gaulish people! Mercury rules over trade, travel, communication and commerce, plus he invented the arts. The Southern Gauls actually had accepted Hermes, the earlier Greek version of Mercury, into their culture centuries before Caesar visited, so in a way Mercury was not really a new God to those Gauls.
“Some Gaulish Mercury statues showed him with three faces (which happens with other Gaulish Gods, signifying great strength) and three phalluses. Sometimes he is portrayed bearded and older than the Roman Mercury. Armed with a spear, he was often with the Celtic Goddess Rosmerta. His symbols are a herald’s staff and a money-bag; his animal familiars are goats, sheep and roosters, all of which became new popular animal sacrifices. He sometimes appears with the horned serpent, normally associated with Cernunnos.
“His name is found in Western European city names: Lugdunum (“fort of Lugus”), which was the capital of the Roman province of Gallia Lugdunensis (today Lyon, France); Carlisle, England, which was once Luguvalium; Loudoun in Scotland; Leiden in the Netherlands; Dinlleu in Wales; Lothian in Scotland; and Lugones in Spain. That was once in the territory of the Luggones, one of the 21 tribes of Asturians. There are many personal names linked to Lugus. One is Llewellyn. His own name, however, is rarely written down, even with Mercury. Some scholars believe that the many places with “his name” were really just “brilliant.” His name also may be connected to “oath,” such as putting an oath of destiny on someone. (“I swear you will….”)
“Lugus was also popular with the Celtiberians, especially in the mountains. Three inscriptions of a plural version of his name, the Lugoves, were found in Spain. One inscription, “L. L. Urcico dedicated this, sacred to the Lugoves, to the guild of shoemakers,” interests many scholars because the Brythonic God Lleu in the Mabinogi was a shoemaker. Lleu and the Gaelic Lugh, who has all the skills, are believed to be connected with Lugus.
“The Gaulish Mercury had mountain tops dedicated to him. They were called Mercurii Montes and included Montmartre, the Puy de Dôme, and the Mont de Sène.”
From Steel Bars, Sacred Waters:
“Rosmerta (“the Great Provider”) is the Celtic companion of the Roman God Mercury. Celtic religion required the pairing of a God with a Goddess, but they did not have to be married. Rosmerta, being older, may have been considered Mercury’s mother. She is a mature Goddess who was worshiped in all the Celtic lands in the Roman Empire, being most popular in northern and eastern Gaul. She shared Mercury’s symbols – a winged staff with snakes, a purse, a winged diadem (instead of his winged hat), a rooster or ram – but she also held cornucopias and offering dishes. Her dress is modest and her face serious. She may have a connection to prophecy, but her worshipers knew her best as the provider of material well-being.”
(Viducus Brigantici filius has a beautiful monthly ritual honoring Rosmerta in Steel Bars, Sacred Waters.)
From Steel Bars, Sacred Waters:
“Cissonius is a Gaulish God of trade and protecting travelers. Cissonius was the second most common name for the Gaulish Mercury. In Switzerland, southern Germany and France 17 inscriptions of his name have been found. Cissonius had two different forms. One was typical of Mercury: the young man with the winged helmet and staff. The other was as a man with a beard wearing a helmet who rode a ram while carrying a cup of wine.”
Senobessus Bolgon offers more on the role of Cissonius in Gaulish Reconstructionist Paganism, as well as another deity commonly associated with Mercury, Visucius.
I personally wonder about the influence of Hermes on the Gaulish understanding of Mercury. Early writing about the Celts said they were master magi, nearly obsessed with magic, and Hermes has a strong history as a God of magic. Sorcerer (and master of everything else worth doing) Lugh performs the one eye Crane Position. Lleu is the maternal nephew (or son) of the greatest sorcerer of Wales Gwydion, Himself the maternal nephew of Math, King of Gwynedd and another fabulous magician.
Davies, Sioned, editor and translator, The Mabinogion. Oxford World’s Classics (2007)
Ewing, John Thor, The Birth of Lugh – Óðinn and Loki among the Celts, Sinsear 8, University College Dublin (1995)
Gregory, Lady, Gods and Fighting Men: The Story of the Tuatha De Danann and of the Fianna of Ireland. Public Domain (1905)
Haussler, Ralph, How to identify Celtic religion(s) in Roman Britain and Gaul, Divinidades indigenas em analise, J. d’Encarnacao (ed), (2008)
Haussler, Ralph, Interpretatatio Indigena: Re-Inventing Local Cults in a Global World, Mediterraneo Antico, xv, 1-2 (2012)
Hyllested, Adam, The Precursors of Celtic and Germanic, Proceedings of the 21st Annual UCLA Indo-European Conference (2010)
Nova Roma, http://www.novaroma.org/nr/Roman_religion
Rhys, John, Celtic Folklore: Welsh and Manx. Oxford University Press (1901)
Sjoestedt, Marie-Louise, translated by Myles Dillon, Celtic Gods and Heroes. Dover (2000)
Viducus Brigantici filius, Deo Mercurio, http://www.deomercurio.be/en/