Welsh mythology is a product of medieval Britain. It is found in medieval documents from Wales in various forms, such as poems, prose tales, and triads containing brief references to otherwise forgotten stories. Significantly, the Welsh are, along with the Cornish and the Bretons, the direct cultural successors of the ancient Celts of Britain. Hence, a traditional view among scholars has been to interpret several figures in Welsh mythology as evolved versions of ancient Celtic gods. But does the evidence really support this view?Celtic Gods in Welsh MythologyPanel of the Mabinogi, by George Sheringham, c. 1887-1937. Source: Wikimedia CommonsWelsh mythology is largely, although not exclusively, set in the Arthurian era. That is, it largely involves figures who are presented as contemporaries of King Arthur. Consider, for example, the Four Branches of the Mabinogi, which tells the story of Pryderi, a prince of Dyfed. Taliesin, King Arthurs chief bard, appears in one of the stories, and several Arthurian stories refer to characters from that narrative.It is known that many of the figures who appear in the Arthurian legends were historical people. Examples include Urien, Gildas, and Maelgwn Gwynedd. However, this does not mean that all the characters in those legends were historical. Some of them appear to be thoroughly mythological. For example, a very fanciful and mythological Arthurian tale is Culhwch and Olwen, dated to c. 1100. Numerous characters from Welsh tradition feature in this story, making it a very useful source. Some scholars believe that several characters in this tale are evolutions of ancient Celtic gods.Remains of a Roman temple dedicated to Nodens, Lydney Park, Gloucestershire. Source: Jeff Collins via GeographExamples include Mabon ap Modron. Both Mabon and his mother Modron are argued to be Celtic divinities, son god and mother goddess, respectively. Another example is Gwyn ap Nudd. Gwyns father, Nudd, is argued to be the Celtic god Nodens, attested in Britain in the Roman era. Gwyn himself is allegedly some kind of divinity who takes people to the underworld.A particularly famous example is Beli Mawr. Although he does not appear in Culhwch and Olwen, many other sources mention him. He is presented in the records as a famous and prominent ancestor figure. His epithet, Mawr, means Great. Therefore, he is Beli the Great. Many scholars in the past have argued that he can be identified with Belenos, the prominent Celtic god attested in Britain and Gaul in the Roman era. This god, Belenos, was likely the Apollo mentioned by Julius Caesar as one of the chief gods of the Celts. However, was he really Beli Mawr from the Welsh tales?Mabon and ModronInscribed stone dedicated to Maponos, Hexham Abbey, Northumberland. Source: Mike Quinn via GeographLet us begin our examination by taking a closer look at the case of Mabon and Modron. The Celtic goddess Dea Matrona is attested on the continent as early as the 1st century BCE. The River Marne was named Matrona after her, as we see in the writings of Julius Caesar. Her name means Mother Goddess. In Roman Britain, there are a number of inscriptions that mention a certain Maponos or Deo Maponos, which means Great Son God. With one deity being attested as Mother and another being attested as Great Son, they would logically have been associated with each other.The name Mabon is definitely an evolution of Maponos, and Modron is likewise an evolution of Matrona. Of course, that does not necessarily mean that real people never used these names. In fact, we know that Mabon was a genuine name used in the Arthurian era.Nevertheless, the fact that Mabon, Great Son, is explicitly made the son of Modron, Mother, is highly suggestive that these figures are indeed evolutions of the Celtic deities from whom their names derive.Origins of NuddCulhwch and Olwen, in Jesus College MS 111, folio 201v, showing Gwyn ap Nudd in the center, c. 1382-1425. Source: Bodleian Library, OxfordWhat about Nudd, another figure who appears in Culhwch and Olwen? There are two main reasons for concluding that he was a Celtic god. The first is that his name, Nudd, appears to be an evolution of Nodens, the name of a Celtic god attested in Britain in the Roman era. Secondly, Welsh texts appear to place his son, Gwyn, in a highly mythological context. For example, Culhwch and Olwen mentions that God had placed the demons of Annwn in him, Annwn being the Welsh Otherworld. Another relevant Welsh text is a poem found in the Black Book of Carmarthen. This poem refers to Gwyn as a fairy. It mentions various warriors whom he saw fall in battle. In the poem, Gwyn himself states that he is the escort of the grave.For these reasons, Gwyn is viewed as an entirely mythological figure, meaning that his father, Nudd, could certainly be the evolution of the Celtic god Nodens.Yarrow Stone with the inscription for Nudus son of Liberalis, Selkirkshire, Scotland, c. 6th century. Source: Canmore National Record of the Historic EnvironmentIs there an attested Celtic god from whose name Gwyn could be derived, and could this god plausibly be connected to Nodens, as in the case of Mabon ap Modron? The answer is no. If there were, then the case for Gwyn and his father being Celtic gods would be strong. As it is, the fact that Gwyn is heavily associated with mythological characteristics is not particularly significant. We see the same phenomenon with figures who are known to be historical.Taliesin, for example, is widely accepted as historical. Yet Welsh sources present him in an equally mythological way. He portrays himself as having been present for all manner of important events throughout history, and one tale has him transform into an animal.The name Nudd, whether it derives from Nodens or not, is well attested in this period. It is even found in a stone inscription dating back to the 6th century. The name Gwyn is also associated with numerous figures who are not obviously mythological.Origins of Beli MawrJesus College MS 20, folio 34v, showing Beli Mawr at the end of the fourth line, c. 14th century. Source: Bodleian Library, OxfordWhat about Beli Mawr, the famous ancestor figure? Welsh texts make him the father of Cassivellaunus, the Brythonic king who fought against Julius Caesar when he invaded Britain in 54 BCE. What is the basis for viewing him as a Celtic god? Put simply, the basis is that his name is considered to have derived from Belenos, and he has a prominent place in Welsh tradition. However, is this really enough to justify identifying him as a Celtic god?Nothing about him in Welsh tradition suggests that he was viewed as anything more than a regular human. The only suggestion that he was viewed as connected to anything remotely divine is that his wife, Anna, is said to have been the cousin of the Virgin Mary. Aside from that, he seems completely ordinary. While he does have the epithet Mawr or Great, numerous historical figures were given that epithet in Welsh tradition.The name Beli, while possibly deriving from Belenos, was used by numerous individuals in Welsh history, as were the related forms Belin and Belinus. Therefore, there is really nothing about Beli Mawr that suggests that he was a Celtic god.Celtic God of Annwn and the Welsh OtherworldOpening of Preiddeu Annwn, in MS Peniarth 2, folio 25v, which mentions the nine magical maidens of Annwn, c. 1300-1350. Source: National Library of WalesFinally, let us consider an example of a Celtic god which, like Maponos and Matrona, does appear to have found its way into Welsh mythology. This time, we will work in the opposite direction. In the 1st century CE, the writer Pomponius Mela mentioned that the Isle of Sena, just off northwest Brittany, France, was dedicated to a Gallic divinity. He explains that there was an oracle on the island, and there were nine priestesses who served there. They were alleged to have the magical abilities of healing and shape-shifting.The connections between this record and the tale of Avalon are striking. Avalon is equivalent to Annwn in Welsh mythology, with which nine magical maidens are also associated. Therefore, the ruler of Avalon, or Annwn, can presumably be associated with the Celtic divinity mentioned by Pomponius Mela.Exactly which figure from Welsh mythology may be associated with this Celtic god is difficult to determine, since Welsh tradition speaks of several different rulers of Annwn. Examples include Afallach, Arawn, Hafgan, and Gwyn. However, Afallach seems to be the most likely candidate.Are There Really Celtic Gods in Welsh Mythology?Scene from the Gundestrup Cauldron depicting a Celtic god, Denmark, c. 1st century BCE. Source: National Museum of DenmarkIn conclusion, the traditional understanding that Welsh mythology preserves some relics from ancient Celtic mythology is not entirely without basis. There is a very good basis for concluding that Mabon and his mother Modron are direct evolutions of the Celtic god Maponos and the goddess Matrona, respectively. Furthermore, it is very likely that the Celtic god who was worshipped on the Isle of Sena was preserved in Welsh mythology, possibly in the guise of King Afallach.On the other hand, some popular identifications of supposed Celtic gods in Welsh mythology are far less likely. The identification of Beli Mawr as the god Belenos is founded on a very weak basis, with nothing substantial to recommend it. The argument that Gwyn was a Celtic god and his father Nudd was Nodens is more convincing, but still without solid evidence. Both Gwyn and Nudd were common names in that era, as was the practice of portraying historical figures with mythological characteristics.