Ffichti (Picts), Gwyddyl Ffichti, Brythons (or British), and the Cewri (aboriginal giants). Both the Gwyddylaid and Brythons are Celts. In addition there are individuals from further races, including a Jewish family, Rhun's Greek father, while it is suggested that Myrddin may have come from Atlantis, or be the last of the Coranians. Several Saxon characters also represent Britain's latest conquerors. Porius himself has ancestors who were Romans, Brythons, Cewri or giants, and the Forest people, and the novel highlights how the multi-cultural nature of Britain, and the varied religious beliefs of different ethnic groups, is shaping history. Amongst the beliefs existing in 5th-century Wales are Christianity, the Pelagian heresy, Mithraism, Pythagorism, Druidism, and Judaism. As well Porius is concerned with the idea of possible alternative histories that might have arisen from this significant transitional age, if a different religion than Christianity (or different version of Christianity) had triumphed. In Mortal Strife, his wartime propaganda work of 1942, Powys suggests that the multi-racial mixture of contemporary Britains will help in the fight against the more racially pure Germans. In 499 AD, various ethnic cultures and their differing religious beliefs are involved in a conflict from which Christianity will eventually triumph. At this time, however, even within Christianity there is the conflict between the doctrines of Augustine of Hippo, along whose theological lines it subsequently developed, and the competing heresy of Pelagianism, to which this novel's protagonist is an adherent: "Porius owes to Pelagius the imaginative impulse that liberates him by allowing him to use his imagination to create the future through the soul's inmost desire". In Porius Powys suggests, through the protagonist's Pelagianism, an alternative to the authoritarian direction that, he believes, Christianity actually took. Furthermore Porius soon after the novel opens comes under the influence of Myrddin: "a living, almost divine embodiment of the teaching of […] Pelagius." At the end of the first half of the 20th century Powys was witnessing the demise of Christianity and the rise of the new religions of the 20th century. Porius and the 20th century Porius takes place during the week of "October 18, to October 25, A.D. 499", a time Powys claims when "There appears to be an absolute blank, as far as documentary evidence goes, with regard to the history of Britain". Making a claim similar to that of other historians and historical novelists who try to historicize the Arthurian legend,