Frederick II, Holy Roman Emperor

Frederick II (December 26, 1194 – December 13, 1250), of the Hohenstaufen dynasty, was a pretender to the title of King of the Romans from 1212 and unopposed holder of that monarchy from 1215. As such, he was King of Germany, and of Italy, and of Burgundy. He was Holy Roman Emperor from his papal coronation in 1220 until his death. His original title was King of Sicily, which he held as Frederick I from 1198 to death. His other royal titles, accrued for a brief period of his life, were King of Cyprus and Jerusalem by virtue of marriage and his connection with the Crusades.

He was raised and lived most of his life in Sicily, his mother, Constance, being the daughter of Roger II of Sicily. His empire was frequently at war with the Papal States, so it is unsurprising that he was excommunicated twice and often vilified in chronicles of the time. Pope Gregory IX went so far as to call him the Antichrist. After his death the idea of his second coming where he would rule a 1000-year reich took hold, possibly in part because of this.

He was known in his own time as Stupor mundi ("wonder of the world"). Said to speak nine languages and be literate in seven [Armstrong 2001, p. 415] (at a time when many monarchs and nobles were not literate at all), Frederick was a very modern ruler for his times, being a patron of science and the arts.

He was patron of the Sicilian School of poetry. His royal court in Palermo, from around 1220 to his death, saw the first use of a literary form of an Italo-Romance language, Sicilian. The poetry that emanated from the school predates the use of the Tuscan idiom as the preferred lingua franca of the Italian peninsula by at least a century. The school and its poetry were well known to Dante and his peers and had a significant influence on the literary form of what was eventually to become the modern Italian.

Life

Early years

Born in Jesi, near Ancona, Frederick was the son of the emperor Henry VI. Some chronicles say that his mother, the forty-year-old Constance, gave birth to him in a public square in order in order to forestall any doubt about his origin. Frederick was baptised in Assisi.

The birth of Frederick II

In 1196 at Frankfurt am Main the child Frederick was elected to become King of the Germans. His rights in Germany were disputed by Henry's brother Philip of Swabia and Otto IV. At the death of his father in 1197, the two-year-old Frederick was in Italy travelling towards Germany when the bad news reached his guardian, Conrad of Spoleto. Frederick was hastily brought back to Constance in Palermo.
His mother, Constance of Sicily, had been in her own right queen of Sicily; she had Frederick crowned King of Sicily and established herself as regent. In Frederick's name she dissolved Sicily's ties to the Empire, sending home his German counsellors (notably Markward of Anweiler and Gualtiero da Pagliara), and renouncing his claims to the German kingship and empire.

Upon Constance's death in 1198, Pope Innocent III succeeded as Frederick's guardian until he was of age. Frederick was crowned King of Sicily on May 17, 1198.

See also Personality

Emperor

Otto of Brunswick was crowned Holy Roman Emperor by Pope Innocent III in 1209. In September 1211 at the Diet of Nuremberg Frederick was elected in absentia as German King by a rebellious faction backed by Innocent, who had fallen out with Otto and excommunicated him; he was again elected in 1212 and crowned December 9, 1212 in Mainz; yet another coronation ceremony took place in 1215. Frederick's authority in Germany remained tenuous, and he was recognized only in southern Germany: in northern Germany, the center of Guelph power, Otto continued to hold the reins of royal and imperial power despite excommunication. But Otto's decisive military defeat at Bouvines forced him to withdraw to the Guelph hereditary lands, where he died, virtually without supporters, in 1218. (See also Guelphs and Ghibellines). The German princes, supported by Innocent III, again elected Frederick king of Germany in 1215, and the pope crowned him king in Aachen on July 23, 1215. It was not, however, until another five years had passed, and only after further negotiations between Frederick, Innocent III, and Honorius III—who succeeded to the papacy after Innocent's death in 1216—that Frederick was crowned Holy Roman Emperor in Rome by Honorius III on November 22, 1220. At the same time his oldest son Henry took the title of King of the Romans.

Unlike most Holy Roman emperors, Frederick spent little of his life in Germany. After his coronation in 1220, he remained either in the Kingdom of Sicily or on Crusade until 1236, when he made his last journey to Germany. (At this time, the Kingdom of Sicily, with its capital at Palermo, extended onto the Italian mainland to include most of southern Italy.) He returned to Italy in 1237 and stayed there for the remaining thirteen years of his life, represented in Germany by his son Conrad.

In the Kingdom of Sicily, he built on the reform of the laws begun at the Assizes of Ariano in 1140 by his grandfather Roger II. His initiative in this direction was visible as early as the Assizes of Capua (1220) but came to fruition in his promulgation of the Constitutions of Melfi (1231, also known as Liber Augustalis), a collection of laws for his realm that was remarkable for its time and was a source of inspiration for a long time after. It made the Kingdom of Sicily an absolutist monarchy, the first centralized state in Europe to emerge from feudalism; it also set a precedent for the primacy of written law. With relatively small modifications, the Liber Augustalis remained the basis of Sicilian law until 1819.

During this period, he also built the Castel del Monte and in 1224 created the University of Naples: now called Università Federico II, it remained the sole atheneum of Southern Italy for centuries.

The Crusade

At the time he was crowned Emperor, Frederick promised to go on crusade. In preparation for his crusade, Frederick in 1225 married Yolande of Jerusalem, heiress to the Kingdom of Jerusalem, and immediately took steps to assume control of the Kingdom from his new father-in-law, John of Brienne. However, he continued to take his time in setting off, and in 1227, Frederick was excommunicated by Pope Gregory IX for failing to honor his crusading pledge - perhaps unfairly, at this point, as his plans had been delayed by an epidemic, from which he himself had fallen ill. Many contemporary chroniclers doubted the sincerity of Frederick's illness, stating that he had deliberately delayed for selfish reasons, and this attitude can in part be explained by their pro-papal stance. Roger of Wendover, a chronicler of the time, wrote ‘he went to the Mediterranean sea, and embarked with a small retinue; but after pretending to make for the holy land for three days, he said that he was seized with a sudden illness…this conduct of the emperor redounded much to his disgrace, and to the injury of the whole business of the crusade,'(‘Roger of Wendover', Christian Society and the Crusades, ed Peters (Philadelphia 1971)).

He eventually embarked on the crusade the following year (1228), which was looked on by the Pope as a provocation, since the church could not take any part in the honor of the crusade, resulting in a second excommunication. Frederick did not attempt to take Jerusalem by force of arms. Instead, he negotiated restitution of Jerusalem, Nazareth, and Bethlehem to the Kingdom with sultan Al-Kamil, the Ayyubid ruler of the region, who was nervous about possible war with his relatives who ruled Syria and Mesopotamia and wished to avoid further trouble from the Christians.

Frederick II (left) meets al-Kamil (right).

The crusade ended in a truce and in Frederick's coronation as King of Jerusalem on March 18, 1229 — although this was technically improper, as Frederick's wife Yolande, the heiress, had died in the meantime, leaving their infant son Conrad as rightful heir to the kingdom. Frederick's further attempts to rule over the Kingdom of Jerusalem were met by resistance on the part of the barons, led by John of Ibelin, Lord of Beirut. In the mid-1230s, Frederick's viceroy was forced to leave Acre, the capital, and in 1244, Jerusalem itself was lost again to a new Muslim offensive.

Whilst Frederick's seeming bloodless victory in recovering Jerusalem for the cross brought him great prestige in some European circles, his decision to complete the crusade while excommunicated provoked Church hostility. Although in 1231 the Pope lifted Frederick's excommunication at the Peace of San Germano, this decision was taken for a variety of reasons related to the political situation in Europe. Of Frederick's crusade, Philip of Novara, a chronicler of the period, said "The emperor left Acre [after the conclusion of the truce]; hated, cursed, and vilified." (The History of Philip of Novara, Christian Society and the Crusades, ed Peters. Philadelphia, 1971). Overall the success of this crusade, the first successful one after the failures of the fourth and fifth crusades, was adversely affected by the manner in which Frederick carried out negotiations without the support of the church.

The war against the Pope and the Italian Guelphs

While he may have temporarily made his peace with the pope, Frederick found the German princes another matter. In 1231, Frederick's son Henry (who was born 1211 in Sicily, son of Frederick's first wife Constance of Aragon) claimed the crown for himself and allied with the Lombard League. The rebellion failed, though not utterly; Henry was imprisoned in 1235, and replaced in his royal title by his brother Conrad, already the King of Jerusalem; Frederick won a decisive battle in Cortenuova over the Lombard League in 1237.

Frederick celebrated it with a triumph in Cremona in the manner of an ancient Roman emperor, with the captured carroccio (later sent to the commune of Rome) and an elephant. He rejected any suit for peace, even from Milan which had sent a great sum of money. This demand of total surrender spurred further resistance from Milan, Brescia, Bologna and Piacenza, and in October 1238 he was forced to raise the siege of Brescia, in the course of which his enemies had tried unsuccessfully to capture him.

Frederick received the news of his excommunication by Gregory IX in the first months of 1239 while his court was in Padova. The emperor responded by expelling the Minorites and the preachers from Lombardy, and electing his son Enzio as Imperial vicar for Northern Italy. Enzio soon annexed the Romagna, Marche and the Duchy of Spoleto, nominally part of the Papal States. The father announced he was to destroy the Republic of Venice, which had sent some ships against Sicily. In December of that year Frederick marched over Toscana, entered triumphantly into Foligno and then in Viterbo, whence he aimed to finally conquer Rome, in order to restore the ancient splendours of the Empire. The siege, however, was ineffective, and Frederick returned to Southern Italy, sacking Benevento (a papal possession). Peace negotiations came to nothing.

In the meantime the Ghibelline city of Ferrara had fallen, and Frederick swept his way northwards capturing Ravenna and, after another long siege, Faenza. The people of Forlì (which kept its Ghibelline stance even after the collapse of Hohenstaufen power) offered their loyal support during the capture of the rival city: as a sign of gratitude, they were granted an augmentation of the communal coat-of-arms with the Hohenstaufen eagle, together with other privileges. This episode shows how the independent cities used the rivalry between Empire and Pope as a mean to obtain the maximum advantage for themselves.

The Pope called a council, but Ghibelline Pisa thwarted it, capturing cardinals and prelates on a ship sailing from Genoa to Rome. Frederick thought that this time the way into Rome was opened, and he again directed his forces against the Pope, leaving behind him a ruined and burning Umbria. Frederick destroyed Grottaferrata preparing to invade Rome. Then, on August 22, 1240, Gregory died. Frederick, showing that his war was not directed against the Church of Rome but against the Pope, drew back his troops and freed two cardinals from the jail of Capua. Nothing changed, however, in the relationship between Papacy and Empire, as Roman troops assaulted the Imperial garrison in Tivoli and the Emperor soon reached Rome. This back-and-forth situation was repeated again in 1242 and 1243.

His last and fiercest opponent, Innocent IV

A new pope, Innocent IV, was elected on June 25, 1243. He was a member of a noble Imperial family and had some relatives in Frederick's camp, so the Emperor was initially happy with his election. Innocent instead was to become his fiercest enemy. Negotiations began in the summer of 1243, but the situation changed as Viterbo rebelled, instigated by the intriguing Cardinal Ranieri of Viterbo. Frederick could not afford to lose his main stronghold near Rome, and besieged the city. Many authorities state that the Emperor's star began its descent with this move. Innocent convinced him to withdraw his troops, but Ranieri nonetheless had the Imperial garrison slaughtered on November 13. Frederick was enraged. The new Pope was a master diplomat, and Frederick signed a peace treaty, which was soon broken. Innocent showed his true Guelph face, and, together with most of the Cardinals, fled via Genoese galleys to the Ligurian republic, arriving on July 7. His aim was to reach Lyon, where a new coucil was held beginning June 24, 1245. One month later, Innocent IV declared Frederick to be deposed as emperor, characterising him as a "friend of Babylon's sultan", "of Saracen customs", "provided with a harem guarded by eunuchs" like the schismatic emperor of Byzantium and, in sum, a "heretic". The Pope backed Heinrich Raspe, landgrave of Thuringia as his rival for the imperial crown and set in motion a plot to kill Frederick and Enzio, with the support of his (the pope's) brother-in-law Orlando de Rossi, another friend of Frederick's.

The plotters, however, were unmasked by the count of Caserta. The vengeance was terrible: the city of Altavilla, where they had found shelter, was razed, and the guilty were blinded, mutilated and burnt alive or hanged. An attempt to invade the Kingdom of Sicily, under the command of Ranieri, was halted at Spello by Marino of Eboli, Imperial vicar of Spoleto.

Frederick II's troops paid with leather coins, from Chigi Codex, Vatican Library

Innocent also sent a flow of money to Germany to cut off Frederick's power at its source. The archbishops of Köln and Mainz also declared Frederick deposed, and in May 1246 a new king was chosen in the person of Heinrich Raspe. On August 5 Heinrich, thanks to the Pope's money, managed to defeat an army of Conrad, son of Frederick, near Frankfurt. But Frederick strengthened his position in Southern Germany, acquiring the Duchy of Austria, whose duke had died without heirs, and one year later Heinrich died as well. The new anti-king was William II, Count of Holland.

Between February and March 1247 Frederick settled the situation in Italy by means of the diet of Terni, naming his relatives or friends as vicars of the various lands. He married his son Manfred to the daughter of Amedeo di Savoia and secured the submission of the marquis of Monferrato. On his part, Innocent asked protection from the King of France, Louis IX; but the king was a friend of the Emperor and believed in his desire for peace. A papal army under the command of Ottaviano degli Ubaldini never reached Lombardy, and the Emperor, accompanied by a massive army, held the next diet in Turin.

The unexpected sally of the Ghibelline cavalry from Parma against Vittoria, from an ancient manuscript

The Battle of Parma and the end

An unexpected event was to change the situation dramatically. In June 1247 the important Lombard city of Parma expelled the Imperial functionaries and sided with the Guelphs. Enzio was not in the city and could do nothing more than ask for help from his father, who came back to lay siege to the rebels, together with his friend Ezzelino III da Romano, tyrant of Verona. The besieged languished as the Emperor waited for them to surrender from starvation. He had a wooden city, which he called "Vittoria", built around the walls, where he kept his treasure and the harem and menagerie, and from where he could attend his favourite hunting expeditions. On February 18, 1248, during one of these absences, the camp was suddenly assaulted and taken, and in the ensuing Battle of Parma the Imperial side was routed. Frederick lost the Imperial treasure and with it any hope of maintaining the impetus of his struggle against the rebellious communes and against the pope, who began plans for a crusade against Sicily. Frederick soon recovered and rebuilt an army, but this defeat encouraged resistance in many cities that could no longer bear the fiscal burden of his regime: Romagna, Marche and Spoleto were lost.

In February 1249 Frederick fired his advisor and prime minister, the famous jurist and poet Pier delle Vigne on charges of speculation and embezzlement. Some historians suggest that Pier was planning to betray the Emperor, who, according to Matthew of Paris, cried when he discovered the plot. Pier, blinded and in chains, died in Pisa, possibly by suicide. (Even more shocking for Frederick was the capture of his son Enzio of Sardinia by the Bolognese at the Battle of Fossalta, in the May of the same year. Only twenty-three at the time, he was held in a palace in Bologna, where he remained captive until his death in 1272. Frederick lost another son, Richard of Chieti. The struggle continued: the Empire lost Como and Modena, but regained Ravenna. An army sent to invade the Kingdom of Sicily under the command of Cardinal Pietro Capocci was crushed in the Marche at the Battle of Cingoli in 1250. In the first month of that year the indomitable Ranieri of Viterbo died and the Imperial condottieri again reconquered Romagna, Marche and Spoleto, and Conrad, King of the Romans scored several victories in Germany against William of Holland.

The sarcophagus of Frederick II of Hohenstaufen in the Cathedral of Palermo.

Frederick did not take part in of any of these campaigns. He had been ill and probably felt himself tired. Despite the betrayals and the setbacks he had faced in his last years, Frederick died peacefully, wearing the habit of a Cistercian monk, on December 13, 1250 in Castel Fiorentino near Lucera, in Puglia, after an attack of dysentery. At the time of his death, his preeminent position in Europe was challenged but not lost: his testament left his legitimate son Conrad IV the Imperial and Sicilian crowns. Manfred received the principate of Taranto and the government of the Kingdom, Henry the Kingdom of Arles or that of Jerusalem, while the son of Henry VII was entrusted with the Duchy of Austria and the Marquisate of Styria. Frederick's will stipulated that all the lands he had taken from the Church were to be returned to it, all the prisoners freed, and the taxes reduced, provided this did not damage the Empire's prestige.

However, upon Conrad's death a mere four years later, the Hohenstaufen dynasty fell from power and an interregnum began, lasting until 1273, one year after the last Hohenstaufen, Enzio, had died in his prison. During this time, a legend developed that Frederick was not truly dead but merely sleeping in the Kyffhaeuser Mountains and would one day awaken to reestablish his empire. Over time, this legend largely transferred itself to his grandfather, Frederick I, also known as Barbarossa ("Redbeard").

His sarcophagus (made of red porphyry) lies in the cathedral of Palermo beside those of his parents (Henry VI and Constance) as well as his grandfather, the Norman king Roger II of Sicily. A bust of Frederick sits in the Walhalla temple built by Ludwig I of Bavaria.

Personality

His contemporaries called Frederick stupor mundi, the "wonder" — or, more precisely, the "astonishment" — "of the world"; the majority of his contemporaries, subscribing to medieval religious orthodoxy, under which the doctrines promulgated by the Church were supposed to be uniform and universal, were, indeed astonished — and sometimes repelled — by the pronounced individuality of the Hohenstaufen emperor, his temperamental stubbornness, and his unorthodox, nearly unquenchable thirst for knowledge.

Frederick II was a religious sceptic. He is said to have denounced Moses, Jesus, and Muhammad as all being frauds and deceivers of mankind. He delighted in uttering blasphemies and making mocking remarks directed toward Christian sacraments and beliefs. Frederick's religious scepticism was unusual for the era in which he lived, and to his contemporaries, highly shocking and scandalous.

In Palermo, where the three-year-old boy was brought after his mother's death, he was said to have grown up like a street youth. The only benefit from Innocent III's guardianship was that at fourteen years of age he married a twenty-five-year-old widow named Constance, the daughter of the king of Aragon. Both seem to have been happy with the arrangement, and Constance soon bore a son, Henry.

At his coronation, he showed how unusual he was. He wore a brand-new, red coronation robe with a strange ornamentation at the edge. This was an Arabic inscription indicating that the robe dated from the year 528 in the Muslim calendar; it incorporated the Arab benediction: "May the Emperor be received well, may he enjoy vast prosperity, great generosity and high splendor, fame and magnificent endowments, and the fulfillment of his wishes and hopes. May his days and nights go in pleasure without end or change". This coronation robe can be found today in the Schatzkammer of the Kunsthistorisches Museum in Vienna.

Rather than exterminate the Saracens of Sicily, he allowed them to settle on the mainland and build mosques. Not least, he enlisted them in his - Christian - army and even into his personal bodyguards. As Muslim soldiers, they had the advantage of immunity from papal excommunication. For these reasons, among others, Frederick II is listed as a representative member of the sixth region of Dante's Inferno, The Heretics who are burned in tombs.

A further example of how much Frederick differed from his contemporaries was the conduct of his Crusade in the Holy Land. Outside Jerusalem, with the power to take it, he parlayed five months with the Ayyubid Sultan of Egypt al-Kamil about the surrender of the city. The Sultan summoned him into Jerusalem and entertained him in the most lavish fashion. When the muezzin, out of consideration for Frederick, failed to make the morning call to prayer, the emperor declared: "I stayed overnight in Jerusalem, in order to overhear the prayer call of the Muslims and their worthy God". The Saracens had a good opinion of him, so it was no surprise that after five months Jerusalem was handed over to him, taking advantage of the war difficulties of al-Kamil. The fact that this was regarded in the Arab as in the Christian world as high treason did not matter to him. As the Patriarch of Jerusalem refused to crown him king, he set the crown on his own head.

Besides his great tolerance (which, however, did not apply to Christian heretics), he had an unlimited thirst for knowledge and learning. To the horror of his contemporaries, he simply did not believe things that could not be explained by reason. So he forbade trials by ordeal on the firm conviction that in a duel the stronger would always win, whether he was guilty or not. Many of his laws continue to affect life down to the present day, such as the prohibition on physicians acting as their own pharmacists. This was a blow at the charlatanism under which physicians diagnosed dubious maladies and also at the same time in order to sell a useless, even dangerous "cure".

An image from an old copy of De arte venandi cum avibus.

Frederick inherited a love of falconry from his Norman ancestors. According to a source, Frederick replied to a letter in which the Mongol khan invited him to surrender that he would do so provided he was permitted to become the khan's hawker. He mantained up to fifty hawkers a time for his court, and in his letters he requested Arctic gerfalcons from Lübeck and even from Greenland. He commissioned the translation of the treaty De arte venandi cum avibus, by the Arab Moamyn, from his Syrian astrologer Theodor, and he corrected or rewrote it himself during the interminable siege of Faenza. One of the two existing versions was modified by his son Manfred, also a keen adherent of falconry. Frederick loved exotic animals in general: his mobile zoo, with which he impressed the cold cities of Northern Italy and Europe, included hounds, elephants, giraffes, cheetahs, lynxes, leopards and exotic birds.

Frederick was also interested in the stars, and his court was full of astrologers and astronomers. He often sent letters to the leading scholars of the time (not only in Europe) asking for solutions to questions of science, mathematics and physics.

A Damascene chronicler, Sibt ibn al-Jawzi, leaves a physical description of Frederick based on the testimony of those who had seen the emperor in person in Jerusalem. "The Emperor was covered with red hair, was bald and myopic. Had he been a slave, he would not have fetched 200 dirhams at market." His eyes were described variously as blue, or "green like those of a serpent".

Law reforms

His 1241 Edict of Salerno (sometimes called "Constitution of Salerno") made the first legally fixed separation of the occupations of physician and apothecary. Physicians were forbidden to double as pharmacists and the prices of various medicinal remedies were fixed. This became a model for regulation of the practice of pharmacy throughout Europe.

He was not able to extend his legal reforms beyond Sicily to the Empire. In 1232, he was forced by the German princes to promulgate the Statutum in favorem principum ("statute in favor of princes"). It was a charter of aristocratic liberties for German princes at the expense of the lesser nobility and commoners. The princes gained whole power of jurisdiction, and the power to strike their own coins. The emperor lost his right to establish new cities, castles and mints over their territories. The Statutum severely weakened central authority in Germany. From 1232 the vassals of the emperor had a veto over imperial legislative decisions. Every new law established by the emperor had to be approved by the princes.

Summary

Frederick II was considered singular among the European Christian monarchs of the Middle Ages. This was observed even in his own time, although many of his contemporaries, because of his lifelong interest in Islam, saw in him "the Hammer of Christianity", or at the very least a dissenter from Christendom. Many modern medievalists view this as false, holding that Frederick understood himself as a Christian monarch in the sense of a Byzantine emperor, thus as God's Viceroy on earth. Other scholars view him as holding all religion in contempt, citing his rationalism and penchant for blasphemy. Whatever his personal feelings toward religion, certainly submission to the pope did not enter into the matter. This was in line with the Hohenstaufen Kaiseridee, the ideology claiming the Holy Roman Emperor to be the legitimate successor to the Roman emperors.

Modern treatments of Frederick vary from sober evaluation (Stürner) to hero worship (Ernst Kantorowicz). However, all agree on Frederick II's significance as Holy Roman Emperor, even if some of his actions (such as his politics with respect to Germany) remain quite dubious.

Parentage and children

*Parents
**Henry VI, Holy Roman Emperor (son of Frederick I, Holy Roman Emperor and Beatrix of Burgundy)
**Constance of Sicily (daughter of Roger II of Sicily and Beatrice of Rethel)
*Children
**With Constance of Aragon:
***Henry (VII) of Germany
**With Yolande of Jerusalem:
***unnamed daughter, died young
***Conrad IV of Germany:
**With Isabella of England
***Margaret of Sicily, margravine of Meissen
***Henry Charlote of Sicily
***Frederick of Sicily
***Carl Otto of Sicily
**With Bianca Lancia:
***Manfred of Sicily
***Constance (Anna) of Sicily, married John III Ducas Vatatzes
***Violante of Sicily, married Riccardo di Caserta
**With Adelheid Enzio:
***Enzio of Sardinia
**With Richina of Wolfs'oden:
***Margaret of Swabia
**With Matilda of Antioch:
***Frederich of Antioch
**With unknown:
***Selvaggia
***Conrad of Antioch
***Richard of Theate
***Catarina of Marano
***Blanchefleur
***Gerhard
***Frederick of Pettorana

References

* Claudio Rendina, Federico II di Svevia - Lo specchio del mondo, Newton Compton, Rome, 1995, ISBN 8879839578.
* David Abulafia, Frederick II. A Medieval Emperor, Allen Lane the Penguin Press, 1988, ISBN 8806131974 (Italian edition)
* Georgina Masson, Frederick II of Hohenstaufen, Martin Secker & Warburg, 1957, ISBN 8845291073 (Italian edition)
* Karen Armstrong, Holy War - The Crusades and Their Impact on Today's World, Anchor Books, second edition, December 2001, ISBN 0385721404.
* R.H.C. Davis, A History of Medieval Europe, Longman Group UK Limited, Second edition, 1988, ISBN 0582014042
* Amin Maalouf, The Crusades Through Arab Eyes, Shocken, 1989, ISBN 0805208984

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; a Jew, he successfully emigrated in the late 1930's.
* 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.

See also

* Monarchs of Naples and Sicily
* Dukes of Swabia family tree
* Sicilian School

External links

* Catholic Encyclopedia: Frederick II
* Frederick II, Holy Roman emperor and German king. The Columbia Encyclopedia
* Frederick II â€" Encyclopædia Britannica