• Claudio Rendina, Federico II di Svevia - Lo specchio del mondo, Newton Compton, Rome, 1995, ISBN 88-7983-957-8.
• David Abulafia, Frederick II. A Medieval Emperor, Allen Lane the Penguin Press, 1988, ISBN 88-06-13197-4 (Italian edition).
• Georgina Masson, Frederick II of Hohenstaufen, Martin Secker & Warburg, 1957, ISBN 88-452-9107-3 (Italian edition).
• Karen Armstrong, Holy War - The Crusades and Their Impact on Today's World, Anchor Books, second edition, December 2001, ISBN 0-385-72140-4.
• R.H.C. Davis, A History of Medieval Europe, Longman Group UK Limited, second edition, 1988, ISBN 0-582-01404-2.
• Amin Maalouf, The Crusades Through Arab Eyes, Schocken, 1989, ISBN 0-8052-0898-4.
• Geoffrey Barraclough, The Origins of Modern Germany Norton, second edition, Norton, 1984 (2d ed. publ. 1947), ISBN 0-393-30153-2.
• "Bibliographie zur Geschichte Kaiser Friedrichs II. Und der letzten Staufer", by Carl Arnold Willemsen. Pub: Monumenta Germaniae Historica (1986)

In addition, this article uses material from the corresponding article in the German-language Wikipedia, which, in turn, gives the following references; the notes are theirs:

• Klaus van Eickels: Friedrich II., in: Bernd Schneidmüller/Stefan Weinfurter (editors): Die deutschen Herrscher des Mittelalters, Historische Porträts von Heinrich I. bis Maximilian I., Munich 2003, p. 293-314 and p. 585 (Bibliography). An outstanding short biography. Van Eickels also edited a volume of source materials on Frederick II.
• Ernst Kantorowicz: Kaiser Friedrich II., 2. volumes, Stuttgart 1985-86 (Nachdruck der Ausgabe aus den 20er Jahren), Beautifully written, but very romanticized, so to be read with caution. The author belonged to the circle of Stefan George;
• Wolfgang Stürner: Friedrich II. (Gestalten des Mittelalters und der Renaissance), 2 volumes, Darmstadt 1992-2000. The best and most recent biography of Frederick II. Sober and objective, with an extensive guide to other literature on its subject.
• Gunther Wolf (editor).: Stupor mundi. Zur Geschichte Friedrichs II. von Hohenstaufen (Wege der Forschung 101), 2. veränderte Aufl., Darmstadt 1982. An important collection of essays on Frederick II.