Elves (The Elvenpath)
The British Elves are not really a separate race, but humans with an 'Elvish' culture (similar to Tolkien's Elves). They were the bearers of an ancient civilization that existed in the British Isles before the immigration of the Celts, and are the source of the Germanic and Celtic traditions of elves (hence 'British Elves'), as well as the Greek tradition of Hyperborea. It is possible that the Atlantis myth is based on a memory of the civilization of the British Elves.
While tending to be tall and slender, they look like normal humans of European origin (that means that they don't have large pointed ears or any other non-human features commonly associated with 'elves'). They speak Albic languages; in Old Albic, they called themselves Elbi (singular Alba). This self-designation was borrowed into Germanic as *albhaz, hence English elf. The old Celtic name of Britian, Inis Albion, means 'Island of the Elves'.
Elvish society was egalitarian, liberal and democratic. There never was an 'Elvish empire', only a loose confederacy of self-governed polities with elected leaders, with a 'High Table' (Theleca Tara) set up as a coordinating and arbitrating council of representatives elected in the polities. The British Elves were great mariners and sailed the Atlantic, establishing tradeposts along the shorelines.
The Elves believed that the purpose of humankind was to preserve the world and enrich it by creating new and beautiful things, and that in order to fulfill their Purpose, people had to be free. The social ideal was that of the free-lance artisan.
The Elves used a lunisolar calendar based on the Metonic cycle (19 years = 235 months); the year 1 of the Elvish calendar was the year 1823 BCE, the date of their legendary landtaking. This is actually based on the date of the foundation of the Theleca Tara which was in 815 BCE and said to have happened 'seven gross years after the landtaking'. The year began on the first new moon after the spring equinox.
Elvish astronomy was highly advanced, and Elvish scholars developed a 'Copernican' cosmology, with the planets orbiting the Sun rather than the Earth, more than 300 years before Aristarchos of Samos.
Elvish philosophy of nature was similar to modern morphic field theory. Every living being has a soul (nara), and even inanimate objects have a phanara, a kind of form-giving entity, gestalt, or morphic field that resonates with other phaneri. Everything, from the whole universe down to the smallest particles of matter has (or rather, is) a phanara, and thus the universe is a grand hierarchy of nested phaneri; a nara is an espcially strong phanara specific to an individual being.
The Elvish civilization reached the peak of its development around the year 600 BCE. A few decades later, wars with Phoenicians and Celts, combined with inner strife, brought fourth its demise, and the British Isles became dominated by Celtic tribes immigrating from continental Europe, absorbing the Elvish population.