structural:summarization, linguistic:translation, structural:scholar_edition
Significance and legacy

Historians rate Frederick II as a highly significant European monarch of the Middle Ages. This reputation was present even in Frederick's era. Lansing and English, two British historians, argue that medieval Palermo has been overlooked in favor of Paris and London:

One effect of this approach has been to privilege historical winners, aspects of medieval Europe that became important in later centuries, above all the nation state.... Arguably the liveliest cultural innovation in the 13th century was Mediterranean, centered on Frederick II's polyglot court and administration in Palermo.... Sicily and the Italian South in later centuries suffered a long slide into overtaxed poverty and marginality. Textbook narratives therefore focus not on medieval Palermo, with its Muslim and Jewish bureaucracies and Arabic-speaking monarch, but on the historical winners, Paris and London.

Modern medievalists no longer accept the notion, sponsored by the popes, of Frederick as an anti-Christian. They argue that Frederick understood himself as a Christian monarch in the sense of a Byzantine emperor, thus as God's " viceroy " on earth. Whatever his personal feelings toward religion, certainly submission to the pope did not enter into the matter in the slightest. This was in line with the Hohenstaufen Kaiser-Idee, the ideology claiming the Holy Roman Emperor to be the legitimate successor to the Roman Emperors. As his father Henry VI, Frederick established a cosmopolitan court, such as with the black treasury custodian Johannes Morus, and depiction of the different peoples under their rule, which persisted throughout the starting Late Middle Ages.

21-century treatments of Frederick vary from the sober (Wolfgang Stürner) to the dramatic (Ernst Kantorowicz). However, all agree on Frederick II's significance as Holy Roman Emperor. In the judgment of British historian Geoffrey Barraclough, Frederick's extensive concessions to German princes – which he made in the hopes of securing his base for his Italian projects – undid the political power of his predecessors and postponed German unity for centuries. The modern approach to Frederick II tends to be focused on the continuity between Frederick and his predecessors as Kings of Sicily and Holy Roman Emperors, and the similarities between him and other thirteenth-century monarchs. David Abulafia, in a biography subtitled "A Medieval Emperor", argues that Frederick's reputation as an enlightened figure ahead of his time is undeserved, and that Frederick was mostly a conventionally Christian monarch who sought to rule in a conventional medieval manner.

Nietzsche, a prominent philosopher, mentioned Frederick in his book Beyond Good and Evil (Part V, aphorism 200). Nietzsche seems to admire Frederick for resisting the conventional morals of his time and having the courage to create his own moral code to live by. He compares Frederick to figures like Caesar and Leonardo da Vinci, both of whom he sees as embodying strong individualism and, most importantly, the will to power—which Nietzsche believed to be the very core of human greatness.