While we cannot know for certain whether Lúgh made his way into Pictish mythology, or that the Picts celebrated Lúghnasadh, scholars have, for the most part, concluded they were Celts and spoke a Celtic language.

Archaeology suggests that the Picts were Britons who had been in NE Britain since at least the Bronze age. Later immigration from southern Britain, Ireland and Scandinavia is not excluded, and Scandinavian traffic on the east coast was probable from the Bronze Age. The population was probably reinforced by refugees from the south on numerous later occasions, such as the political takeovers of the Romans (1st century AD), the Angles (5th century AD) and the Normans (11th century AD) (see Tarbat Discovery).

If the Picts did celebrate Lúghnashadh, did they see Lúgh as sun god and Lúghnasadh as a sun festival, as modern legends and beliefs suggest?

According to linguists, the name Lugus is a derivation of the Indo-European root *leuk- "light", and the Latin lux and the Welsh lleu (especially (go)leu "light") as cognates. Also, the Breton luc'h and the Cornish lughes have been interpreted to mean "lightning flash."

This interpretation led to the notion that Lúgh is a sun god, which was nurtured by the Victorian obsession with solar myths. Victorian scholars concluded that Lúgh was a solar god and compared his title Lámhfhada ("long-armed") to that of Prithupâni ("broad-handed"), which was given to the Vedic god Savitr (the god of the first light of day), and now this notion is firmly entrenched in Irish folklore and modern pagan belief.

However, in the traditional tales of Lúgh, there is no evidence that he was a solar deity. Lúghnasadh is a time when the spear of Lúgh brings thunderstorms and torrential rains, a welcome respite from Balor's scorching eye (the hot summer sun). From these and other examples it becomes clear that Lúgh is a bringer of storms, not sunlight, and his "light" is the lightning flash, the principal function of his spear.

Likewise, Lúgh decreed that Lúghnasadh would be Funeral Games in honour of his foster mother Tailtu. Also, Caesar associated Lugus with Mercury, not Apollo, and the Gallic Celts created over 400 shrines of Mercury with their image of Lugus.

Any other thoughts on Lúgh, Lúghnasadh and the Picts?