Beli Mawr or Beli ‘the Great’ is Apollo Belenos, Apollo the Bright or Shining One. The earliest Welsh genealogies make his father one Afallach, who as we have seen can be equated with the Irish Ablach of Emain Ablach, the Apple Orchard Otherworld. His mother was ‘Anna’, i.e. the goddess Anu.
In Arthurian romance Beli Mawr is called Pellinore. In the 12th century, Johannes Cornubiensis identified Caer Beli or the Fort of Beli with Ashbury Camp near Week St. Mary in Cornwall. This fort he also termed the ‘Fatale Castrum’ or Deadly Castle. However, this is an error, as Ashbury Camp is an unremarkable hill-fort. Instead, Ashbury, Oxfordshire is the actual site of the original Cair Beli. This is where we find the famous Neolithic chambered tomb now known as Wayland’s Smithy. Wayland was the smith-god of the invading Saxons. The Smithy is near the Uffington White Horse and one of the primary symbols of Belenos in Gaul is the horse.
Beli as Apollo is associated with Stonehenge, as Geoffrey of Monmouth has the Britons slain by the Saxons at this great ritual centre on May 1st or Beltane, the day of ‘Beli’s Fire’. Stonehenge, of course, is just a little south of the Wayland’s Smithy chambered tomb and the Uffington White Horse.
As Stonehenge was a great astronomical observatory concerned primarily with the motion of the sun through the year, a motion which defines our measurement of time, Beli should be invoked for any matter that is time sensitive or requires calculations and computations. He is the horse that unfailingly gallops across the sky 365 days a year. As such, he is also useful for purposes of steadfastness and determination or single-mindedness of purpose. He is a prophet in the sense that like the future, the course of the sun is always predictable. Finally, he is the god of resurrection, as the sun is reborn every Winter Solstice. Archaeo-astronomers have confirmed that the Winter Solstice was observed annually at Stonehenge.
Excerpt from the book The Secrets of Avalon by August Hunt.
http://avaloniabooks.co.uk/221/catalogue/celtic-mythology/secrets-of-avalon-by-august-hunt/ for details.