Norman Cohn,
The Pursuit of the Millennium, 2nd ed. (New York: Harper & Brothers, 1961), p. xiv:
But in the history of social behaviour there certainly are some patterns which in their main outlines recur again and again, revealing as they do so similarities which become ever more recognisable. And this is nowhere more evident than in the case of highly emotional mass movements such as form the subject-matter of this book. It has happened countless times that people have grouped themselves in millennial movements of one kind or another. It has happened at many different periods of history, in many different parts of the world and in societies which have differed greatly in their technologies and institutions, values and beliefs. These movements have varied in tone from the most violent aggressiveness to the mildest pacifism and in aim from the most ethereal spirituality to the most earthbound materialism; there is no counting the possible ways of imagining the Millennium and the route to it. But similarities can present themselves as well as differences; and the more carefully one compares the outbreaks of militant social chiliasm during the later Middle Ages with modern totalitarian movements the more remarkable the similarities appear. The old symbols and the old slogans have indeed disappeared, to be replaced by new ones; but the structure of the basic phantasies seems to have changed scarcely at all.
Id., p. 308:
And such a revolutionary movement is of a peculiar kind, in that its aims and promises
are boundless. A social struggle is imagined as uniquely important, different in kind
from all other struggles known to history, a cataclysm from which the
world is to emerge totally transformed and redeemed.
Id., pp. 318-319:
For what the propheta offered to his followers was not simply a chance to improve their lot and to escape from pressing anxieties — it was also, and above all, the prospect of carrying out a divinely ordained mission of stupendous, unique importance. This phantasy quickly came to enthrall them in their turn. And what followed then was the formation of a group of a peculiar kind, a true prototype of a modern totalitarian party: a restlessly dynamic and utterly ruthless group which, obsessed by the apocalyptic phantasy and filled with the conviction of its own infallibility, set itself infinitely above the rest of humanity and recognised no claims save that of its own supposed mission. And finally this group might — though it did not always — succeed in imposing its leadership on the great mass of the disoriented, the perplexed and the frightened.
A boundless, millennial promise made with boundless, prophet-like conviction to a number of rootless and desperate men in the midst of a society where traditional norms and relationships are disintegrating — here, it would seem, lay the source of that peculiar subterranean fascism which subsisted as a perpetual menace to the structure of medieval society. It may be suggested that here, too, lies the source of the giant fanaticisms which in our day have convulsed the world.