"The Mythology of Ancient Britain and Ireland" is one of the finest titles within the early 20th century creation series, penned by Charles Squire, and somewhat refining the same ideas in Anwyl's "Celtic Religion."It traces the linguistic and mythological development of Arthurian and similar folklore and pseudohistory in the British Isles from their ancient ancestry many, many centuries prior, with Celtic deities and forces which were transmogrified over time in accordance with the adopting of Christianity, and changing political and social tides.