When the Holy Roman (i.e. German) Emperor Henry VI died in 1197 his son Frederick von Hohenstaufen was, thanks to Henry's marriage to the Sicilian Heiress, Constance, potentially the greatest threat that the hierocratically-inclined papacy would ever have to face. As heir to the Norman conquests in Southern Italy and an imperial claimant he could come to threaten the temporal power of the popes on the only two fronts that mattered territorially. As heir to the Hohenstaufen vision of the empire's universal supremacy he could pose a threat to the papacy's parallel claims to universal sovereignty within Christendom. But when Henry VI died Frederick was barely three years old: the threat lay in the future.
In 1198 Frederick, who had, reasonably enough, been passed over in the imperial election, was crowned (with a very small crown, presumably) King of Sicily at Palermo. His widowed mother had little choice but to seek alliance with the most powerful authority available to safeguard his inheritance. This was the pope, Innocent III, whose bill for the provision of this protection was naturally high. Papal claims to suzerainty over Sicily and Apulia were revived—Constance surrendered these receiving them back as papal fiefs. A tribute was imposed; the right of the Norman kings to nominate bishops was surrendered and court cases involving the clergy were remitted to ecclesiastical jurisdiction (except in cases of high treason). Then, at the close of this same year, Constance herself fell ill and died.
Frederick was thus raised, from a very early age, as a ward of the pope. This circumstance does not, however, appear to have had a preponderant influence upon the determination of his character, aims and policies. Frederick attained his majority at the age of fourteen (in December 1208) and on two occasions within the next two years he was engaged in fairly serious, or at least portentous, disputes with Innocent; in 1209 he insisted on his right to nominate the Bishop of Palermo and in 1210, having dismissed the Bishop of Catania as Chancellor, he refused, despite strongly-worded papal admonitions, to reinstate him.
Nonetheless when Otto (who, following the murder of the Ghibillene candidate, Philip, had succeeded to the imperial throne) invaded Southern Italy in 1211, thus raising the awful spectre of immediate encirclement, Innocent excommunicated him, sanctioned his deposition and acquiesced in the election of Frederick as "King of the Romans" (i.e. Holy Roman Emperor In Waiting). Presumably he felt that Frederick would prove more tractable, more amenable to pressure, than Otto—if the papacy had to be hemmed in on all sides let it be by a young and hopefully malleable papal protege.
In any event Innocent was content to secure assurances from Frederick. At Messina in February 1212 Frederick agreed to swear:—
...in the presence of the Papal Legate fidelity to you and your successors, and promise that if you or your successors come to part of the realm, and we, called by you, can come without peril to your presence we will personally do liege homage to you (quoted in Masson, Frederick II, p 44).
That homage was performed shortly afterwards at Rome when Frederick also swore to renounce the Kingdom of Sicily; handing it over to his son Henry, during whose minority it was to be administered by a papally-appointed regent. Thus was the threat of encirclement apparently staved off: thus was immense trouble stored up for the future.
From Rome Frederick proceeded into Germany where, at Frankfurt on the 5th of December 1212, he was acclaimed as King of the Romans, or Emperor-elect (he would not become emperor proper until his consecration at Rome). Following Otto's disastrous defeat at Bouvines Frederick was crowned at Aachen on July 24th 1215 at which time he, very imprudently as it turned out, vowed to go on crusade. On the 22nd November 1220 he was finally crowned emperor in Rome by Pope Honorius III (Innocent having died in 1216).
In the interim Frederick had succeeded in having young Henry elected King of the Romans. Though he assured Honorius that he had no intention of integrating Sicily into the empire saying: "Even if the Church had no right over the Kingdom of Apulia and Sicily I would freely grant that Kingdom to the Pope rather than attach it to the Empire, should I die without lawful heirs" (quoted, Allshorn, Stupor Mundi p 53) he clearly meant to hand on the Hohenstaufen inheritance undivided to his son. Having promised Innocent that he would keep Henry out of the empire Frederick now promised Honorius that he would keep Henry out of the Kingdom of Sicily. That his second promise was as insincere as his first was demonstrated when, at Barletta, on his way at last to Palestine, he named Henry as his successor to the Kingdom of Sicily.
While in Germany Frederick set about, in effect, undoing the centralisation of imperial power achieved under Barbarossa. In July 1213 he issued the Bull of Eger, a reaffirmation of Otto's Charter of Speyer which "went far towards creating an ecclesiatical state, or states, within the realm of Germany" (Masson, op cit p 54). These tendencies to disintegration were confirmed at the Diet of Mainz in August 1235 at which the Constitution of Fifteen Chapters was issued. In this "the authority of the Princes and higher ecclesiastics was maintained" (Allshorn, op cit p 139); maintained necessarily against imperial power.
In Germany Frederick was primarily concerned to secure the support of imperial electors whose right to depose him he at first implicitly (when he accepted their deposition of Otto) and later explicitly acknowledged. Essentially he was bowing to the logic of a situation over which he had no real control. His policies for the governance of the Kingdom of Sicily where his freedom of action was so much greater were that much more considered. In the Chapters of Capua and the Constitutions of Melfi, based upon the solid legislative and administrative achievements of his Norman predecessors (especially Roger II's Assizes of Ariano), Frederick set about centralising power and authority in the hands of the king and officials directly answerable to him.
His pursuit of those aims at Capua involved Frederick in an attempt to restore the legal and political situation to what it had been in the time of his grandfather, William II. Royal domains, which had fragmented during Frederick's minority and his absence in Germany, were to be restored by means of an investigation of titles to lands and privileges—any dating from the death of William II had to be confirmed by the Royal Chancery. Castles built since William's death were to be handed over to the crown; justice was entrusted to crown-appointed judges; cities were to be governed by royal baliffs (as opposed to elected mayors) and taxes were imposed (assessed to begin with at the rates applying when his mother died) from which the clergy was not immune.
Eleven years later following a general legal survey, the foundations established at Capua were built upon in the promulgation of what Masson calls "the first great legal code of the Middle Ages" (though this is to ignore Henry Plantagenet's Assizes of Clarendon which were earlier and ultimately of greater significance, partly because they were much less far reaching). At Melfi the centralisation of administration was extended: free legal assistance was ordered to be provided for widows, orphans and the poor; bail was introduced in most cases; trial by ordeal was abolished and trial by combat restricted; the elementary feudal right to private war was suppressed; canon law provisions against heresy were adopted but organised non-Christian religions were tolerated; trade was encouraged; serfdom was abolished on the royal domains and discouraged elsewhere; assemblies of the third estate were summoned (for purposes of acclaimation rather than deliberation or legislation) for the first time in Medieval Europe and the University of Naples was founded with a uniquely liberal curriculum.
It must be stressed that while much of the individual legislation originated with Frederick the impulse behind it did not. He was following in the footsteps of Roger and William. Again, though he had incomporably greater freedom of action in Sicily than in Germany, the logic of the situation to a large extent determined the nature of his political activity there also. Certainly, it was the logic of the situation and nothing in the way of personal idiosyncracy which involved him at this point in an entirely inevitable conflict, on two fronts, with the papacy.
In the first instance Frederick's concern to recover all the authority exercised by previous kings of Sicily and establish a centralised administration there necessarily led to conflict with the church over such vital matters as the election of bishops. Earlier kings had simply appointed their bishops but both Constance and later Frederick had had to agree that the approval of both the Pope and the King was necessary before an election could be confirmed. In 1225 the Pope attempted to increase his power by alone appointing bishops to any see which remained vacant for more than six months. Frederick replied by threatening to keep such appointees out of Sicily. In the long-term such a situation, whatever the personal inclination of the protagonists, was simply not amenable to compromise. The conflict was institutional rather than personal.
Similarly, once Frederick had accepted election to the imperial throne (which because of the threat to him from Otto, and his own Swabian inheritance, was unavoidable, even if he had wanted to avoid it) his primary concerns and those of the papacy were mutually exclusive. On the one hand, Frederick had no choice but to secure a safe route to Germany, which necessarily involved the subordination of the Lombard cities. On the other, the concern of the papacy to maintain its independence and freedom of action necessarily involved it in attempts to secure the integrity of the papal states and the existence of a Lombard "buffer zone" between itself and the overwhelming power of the empire. Compromise between two such institutional imperatives was utterly impossible.
Conflict was so basically unavoidable that the forms in which it occurred—Lombard submissions and rebellions, imperial expeditions, papal excommunications, general councils and depositions—must be seen as incidental. Only Frederick's highly unorthodox crusade stands out of a mass of tedious detail.
That expedition by an excommunicated crusader, ending as it did in a purely diplomatic victory, was certainly unique. The limited gains made were, however, never in the least bit likely to endure. One man's crusade being another man's jihad, Frederick's papalist critics were perfectly correct to insist that the non-military acquisition of Jerusalem provided no basis for its, necessarily military, retention.
The success of his negotiations with the Sultan of Egypt, al-Kamil, mark the one point at which Frederick's highly attractive and eccentric personality could perhaps be said to have significantly influenced the nature of his political activity. It may be that the literary, artistically, scientifically, and philosophically inclined emperor talked rather than fought simply because he found sophisticated conversation more congenial. But if so it is the only time at which his personal predelictions can have been a dominant factor. In the rest of his public career he was neither the pre-Lutheran Protestant nor the prototype of an enlightened despot that later ages have imagined. In private he may have been a renaissance man born two hundred years too soon but where it counted he was very much a product of the Middle Ages—a Hohenstaufen who, having come into the Hohenstaufen inheritance, intended to hand it on intact (and, as such, born at least one hundred years too late).