Powys suggests that it is "therefore highly probable" that King Arthur ruled at the time of this "historic blank". This is a time when Roman influence was still strong in Britain, although the Roman army left in 410 AD and the Saxons had established settlements in England. Powys deliberate chose a point of major transition in the history of Britain, with on the one hand the replacing of Roman traditions with Saxon rule, along with the coming of Christianity. There are parallels with contemporary history: "The Dark Ages and the 1930s are the periods of what Powys, in Yeatsian phrase calls 'appalling transition' ". There was the clear possibility of another "Saxon" invasion when Powys began writing Porius in 1942. In prefatory comments, probably written around 1949, at the time of the beginning of the Cold War, Powys suggests that, As we contemplate the historic background to ... the last year of the fifth century [sic], it is impossible not to think of the background of human life from which we watch the first half of the twentieth century dissolve into the second half. As the old gods were departing then, so the old gods are departing now. And as the future was dark with the terrifying possibilities of human disaster then, so, today, are we confronted by the possibility of catastrophic world events. Powys makes a similar comment in the "Argument" to Owen Glendower: "the period that formed the immediate background to […] this tale—1400–1416—saw the beginning of one of the most momentous and startling epochs of transition that the world has known". Michael Ballin discusses how, in Porius, "the present is perceived through the spectacles of the past". Likewise distinguished American literary scholar Jerome McGann, in his Times Literary Supplement review article "Marvels and wonders", describes the novel, as "a profound meditation on the twentieth century's abiding social sickness, and on fascism in particular, their emblematic form". Critical reputation Some admirers of Powys have problems with Porius. Literary critic G. Wilson Knight, in his study of John Cowper Powys, The Saturnian Quest (1964), finds that "the detailed historical knowledge is so dense that it clogs the action" and sees a problem in the way the reader expects "historical excitement where the author has no intention of providing them". For Harald Fawkner, a prolific writer on Powys from the University of Stockholm, Sweden, although Powys is "one of the