Originally published in German as Kaiser Friedrich der Zweite in 1927, it was "one of the most discussed history books in Weimar Germany",[1] and has remained highly influential in the reception of Frederick II.

[2] The book depicts Frederick as a heroic personality, a messianic ruler who was "beseeltes Gesetz", the law given soul,[3][4] but also a charismatic and calculating autocrat—"probably the most intolerant emperor that ever the West begot".

The book was a product of Kantorowicz's association with the esoteric literary circle around Stefan George,[7] and stands within a broader tradition of mythically inflected depictions of Frederick II that includes Friedrich Nietzsche's description of him as "the first European".

Kantorowicz frequently invokes an eclectic variety of literary references to enhance his depiction of Frederick, drawing especially on the medieval poetry of Dante and Parzival but also on classical Greek and Roman mythology.

[16] Upon his final excommunication in 1239, for Kantorowicz Frederick becomes at the same time a messianic figure and an Antichrist in the sense described by Nietzsche—proclaiming himself "the Hammer, the Doom of the World", he begins to construct a new church around himself.

Albert Brackmann, a prominent German medievalist and later Nazi propagandist, criticised Kantorowicz in a lengthy review essay published in 1929 for using "methodologically false means" to arrive at his conception of Frederick.

[31] After World War II he stated that the work was "out of date and runs the risk of encouraging an outmoded nationalism"—though he also rejected the description of the book by the Italian historian Ernesto Pontieri [it] as a prototypical example of Nazism.

[30] The American medieval historian Robert E. Lerner, on the other hand, posited in 1991 that Kantorowicz's methodology may be seen as part of a general attack on the values of the Enlightenment, which manifested in the George circle as much as in Nazism.

[33][34] Cantor's account has been widely criticized, however, described as "irresponsible misrepresentation" and "preposterous" by Lerner,[35][36] "inappropriate" and "deeply regrettable" by the Cambridge medievalist David Abulafia,[34] and "a tissue of falsehoods and half-truths" by Leyser.

[39] The Anglo-Irish philologist Emily Lorimer was commissioned by Helen Waddell at the publishing firm Constable and Company in 1930 to prepare an English translation of the book, which appeared with Kantorowicz's approval the following year.