§ 42. The Papal Conflict with Frederick II Begun.

Between the death of Innocent III. and the election of Boniface VIII., a period of eighty years, sixteen popes sat on the throne, several of whom were worthy successors of the greatest of the pontiffs. The earlier half of the period, 1216 - 1250, was filled with the gigantic struggle between the papacy and Frederick II., emperor of Germany and king of Sicily. The latter half, 1250 - 1294, was marked by the establishment of peace between the papacy and empire, and the dominance of the French, or Norman, influence over the papacy.
Scarcely was Innocent in his grave when Frederick II. began to play his distinguished role, and to engage the papacy in its last great struggle with the empire, a desperate struggle, as it proved to be, in which the empire was at last completely humbled. The struggle kept Europe in turmoil for nearly forty years, and was waged with three popes, Honorius III., Gregory IX., and Innocent IV., the last two, men of notable ability. During all this time Frederick was the most conspicuous figure in Christendom. The struggle was carried on not only in the usual ways of diplomacy and arms, but by written appeals to the court of European opinion.
Frederick II., the grandson of Frederick Barbarossa, was born near Ancona, 1194. His father, Henry VI., had joined Sicily to the empire by his marriage with the Norman princess Constance, through whom Frederick inherited the warm blood of the south. By preference and training, as well as birth, he was a thorough Italian. He tarried on German soil only long enough to insure his crown and to put down the rebellion of his son. He preferred to hold his court at Palermo, which in his letters he called "the Happy City." The Romans elected him king in 1196, and at his father's death a year later he became king of Sicily. The mother soon followed, and by her will "the child of Apulia," as Frederick was called, a boy then in his fourth year, passed under the guardian care of Innocent III. After Otto's star had set, he was crowned king at Frankfurt, 1212, and at Aachen, 1215. Frederick was not twenty when Innocent's career came to an end.
Honorius III., 1216 - 1227, was without the ambition or genius of his predecessor Innocent III. He confirmed the rules and witnessed the extraordinary growth of the two great mendicant orders of St. Francis and St. Dominic. He crowned Peter of Courtenay, emperor of Byzantium, the only Byzantine emperor to receive his crown in Rome. The pope's one passion was the deliverance of Jerusalem. To accomplish this, he was forced to look to Frederick. To induce him to fulfill the vow made at his coronation, in 1215, to lead a crusade, was the main effort of his pontificate. The year 1217, the date set for the crusade to start, passed by. Honorius fixed date after date with Frederick, but the emperor had other plans and found excuses for delay. In 1220 he and his wife Constantia received the imperial crown at the hands of the pope in Rome. For the second time Frederick took the cross. He also seemed to give proof of piety by ratifying the privileges of the Church, announcing his determination to suppress heresy, and exempting all churches and clerics from taxation. In the meantime his son Henry had been elected king of the Romans, and by that act and the pope's subsequent ratification the very thing was accomplished which it had been Innocent's shrewd policy to prevent; namely, the renewal of the union of the empire and the kingdom of Sicily in one hand. Frederick was pursuing his own course, but to appease Honorius he renewed the pledge whereby Sicily was to remain a fief of the papal see.
The fall of Damietta, in 1221, was adapted to fire a sincere crusader's zeal; but Frederick was too much engaged in pleasure and absorbed in his scheme for extending his power in Italy to give much attention to the rescue of the holy places. In hope of inflaming his zeal and hastening the departure of the crusade, Honorius encouraged the emperor's marriage with Iolanthe, daughter of John of Brienne, king of Jerusalem, and heiress of the crown. The nuptials were no sooner celebrated than Frederick assumed the title of king of Jerusalem; but he continued to show no sign of making haste. His aggravating delays were enough to wear out a more amiable disposition than even Honorius possessed. A final agreement was made between them in 1225, which gave the emperor a respite of two years more, and he swore upon penalty of excommunication to set forth October, 1227. Four months before the date appointed for the crusade Honorius died.
The last year of Honorius's reign, Frederick entered openly upon the policy which involved him in repeated wars with the papacy and the towns of Northern Italy. He renewed the imperial claims to the Lombard cities. Upon these claims the Apostolic see could not look with complacency, for, if realized, they would have made Frederick the sovereign of Italy and cramped the temporal power of the papacy within a limited and at best an uncertain area.

§ 43. Gregory IX. and Frederick II. 1227 - 1241.

An antagonist of different metal was Gregory IX., 1227 - 1241. Innocent III., whose nephew he was, seemed to have risen again from the grave in him. Although in years he was more than twice as old as the emperor,238 Gregory was clearly his match in vigor of mind and dauntless bravery, and greatly his superior in moral purpose. In asserting the exorbitant claims of the papacy he was not excelled by any of the popes. He was famed for eloquence and was an expert in the canon law.
Setting aside Frederick's spurious pretexts for delaying the crusade, Gregory in the first days of his pontificate insisted upon his fulfilling his double pledge made at his coronation in 1215 and his coronation as emperor in Rome, 1220. Frederick at last seemed ready to comply. The crusaders assembled at Brindisi, and Frederick actually set off to sea accompanied by the pope's prayers. Within three days of leaving port the expedition returned, driven back by an epidemic, as Frederick asserted, or by Frederick's love of pleasure, as Gregory maintained.
The pope's disappointment knew no bounds. He pronounced against Frederick the excommunication threatened by Honorius. As the sentence was being read in the church at Anagni, the clergy dashed their lighted tapers to the floor to indicate the emperor's going out into darkness. Gregory justified his action in a letter to the Christian princes, and spoke of Frederick as "one whom the Holy See had educated with much care, suckled at its breast, carried on its shoulders, and whom it has frequently rescued from the hands of those seeking his life, whom it has brought up to perfect manhood at much trouble and expense, exalted to the honors of kingly dignity, and finally advanced to the summit of the imperial station, trusting to have him as a wand of defence and the staff of our old age." He declared the plea of the epidemic a frivolous pretence and charged Frederick with evading his promises, casting aside all fear of God, having no respect for Jesus Christ. Heedless of the censures of the Church, and enticed away to the usual pleasures of his kingdom, he had abandoned the Christian army and left the Holy Land exposed to the infidels.
In a vigorous counter appeal to Christendom, Frederick made a bold protest against the unbearable assumption of the papacy, and pointed to the case of John of England as a warning to princes of what they might expect. "She who calls herself my mother," he wrote, "treats me like a stepmother." He denounced the secularization of the Church, and called upon the bishops and clergy to cultivate the self-denial of the Apostles.
In 1228 the excommunication was repeated and places put under the interdict where the emperor might be. Gregory was not without his own troubles at Rome, from which he was compelled to flee and seek refuse at Perugia.
The same year, as if to show his independence of papal dictation and at the same time the sincerity of his crusading purpose, the emperor actually started upon a crusade, usually called the Fifth Crusade. On being informed of the expedition, the pope excommunicated, him for the third time and inhibited the patriarch of Jerusalem and the Military Orders from giving him aid. The expedition was successful in spite of the papal malediction, and entering Jerusalem Frederick crowned himself king in the church of the Holy Sepulchre. Thus we have the singular spectacle of the chief monarch of Christendom conducting a crusade in fulfillment of a vow to two popes while resting under the solemn ban of a third. Yea, the second crusader who entered the Holy City as a conqueror, and the last one to do so, was at the time not only resting under a triple ban, but was excommunicated a fourth time on his return from his expedition to Europe. He was excommunicated for not going, he was excommunicated for going, and he was excommunicated on coming back, though it was not in disgrace but in triumph.
The emperor's troops bearing the cross were met on their return to Europe by the papal army whose banners were inscribed with the keys. Frederick's army was victorious. Diplomacy, however, prevailed, and emperor and pope dined together at Anagni (Sept. 1, 1230) and arranged a treaty.
The truce lasted four years, Gregory in the meantime composing, with the emperor's help, his difficulties with the municipality of Rome. Again he addressed Frederick as "his beloved son in Christ." But formal terms of endearment did not prevent the renewal of the conflict, this time over Frederick's resolution to force his authority upon the Lombard cities. This struggle engaged him in war with the papacy from this time forward to his death, 1235 - 1250. After crushing the rebellion of his son Henry in the North, and seeing his second son Conrad crowned, the emperor hastened south to subdue Lombardy.  "Italy," he wrote in answer to the pope's protests, 1236, "Italy is my heritage, as all the world well knows." His arms seemed to be completely successful by the battle of Cortenuova, 1237. But Gregory abated none of his opposition. "Priests are fathers and masters of kings and princes," he wrote, "and to them is given authority over men's bodies as well as over their souls." It was his policy to thwart at all hazards Frederick's designs upon upper Italy, which he wanted to keep independent of Sicily as a protection to the papal state. The accession of the emperor's favorite son Enzio to the throne of Sardinia, through his marriage with the princess Adelasia, was a new cause of offence to Gregory. For Sardinia was regarded as a papal fief, and the pope had not been consulted in the arrangements leading to the marriage. And so for the fifth time, in 1239, Gregory pronounced upon the emperor the anathema. The sentence charged him with stirring up sedition against the Church in Rome from which Gregory had been forced to flee in the conflicts between the Ghibelline and Guelf parties, with seizing territory belonging to the Holy See, and with violence towards prelates and benefices.
A conflict with the pen followed which has a unique place in the history of the papacy. Both parties made appeal to public opinion, a thing which was novel up to that time. The pope compared the emperor to the beast in the Book of Revelation which "rose out of the sea full of words of blasphemy and had the feet of a bear and the mouth of a lion, and like a leopard in its other parts, opens its mouth in blasphemies against God's name, his dwelling place, and the saints in heaven. This beast strives to grind everything to pieces with his claws and teeth of iron and to trample with his feet on the universal world." He accused Frederick of lies and perjuries, and called him "the son of lies, heaping falsehood on falsehood, robber, blasphemer, a wolf in sheep's clothing, the dragon emitting waters of persecution from his mouth like a river." He made the famous declaration that "as the king of pestilence, Frederick had openly asserted that the world had been deceived by three impostors, Jesus, Moses, and Mohammed, two of these having died in glory and Jesus having been suspended on the cross. Moreover, he had denied the possibility of God's becoming incarnate of a virgin."
This extensive document is, no doubt, one of the most vehement personal fulminations which has ever proceeded from Rome. Epithets could go no further. It is a proof of the great influence of Frederick's personality and the growing spirit of democracy in the Italian cities that the emperor was not wholly shunned by all men and crushed under the dead weight of such fearful condemnations.
In his retort, not to be behind his antagonist in Scripture quotations, Frederick compared Gregory to the rider on the red horse who destroyed peace on the earth. As the pope had called him a beast, bestia, so he would call him a wild beast, belua, antichrist, a second Balaam, who used the prerogative of blessing and cursing for money. He declared that, as God had placed the greater and lesser lights in the heavens, so he had placed the priesthood, sacerdotium, and the empire, imperium, on the earth. But the pope had sought to put the second light into eclipse by denying the purity of Frederick's faith and comparing him to the beast rising out of the sea. Indignantly denying the accusation of the three impostors, he declared his faith in the "only Son of God as coequal with the Father and the Holy Spirit, begotten from the beginning of all worlds. Mohammed's body is suspended in the air, but his soul is given over to the torments of hell."
Gregory went further than words and offered to the count of Artois the imperial crown, which at the instance of his brother, Louis IX. of France, the count declined. The German bishops espoused Frederick’s cause. On the other hand, the mendicant friars proved true allies of the pope. The emperor drove the papal army behind the walls of Rome. In spite of enemies within the city, the aged pontiff went forth from the Lateran in solemn procession, supplicating deliverance and accompanied by all the clergy, carrying the heads of the Apostles Peter and Paul.250  When Frederick retreated, it seemed as if the city had been delivered by a miracle. However untenable we may regard the assumptions of the Apostolic see, we cannot withhold admiration from the brave old pope.
Only one source of possible relief was left to Gregory, a council of the whole Church, and this he summoned to meet in Rome in 1241. Frederick was equal to the emergency, and with the aid of his son Enzio checkmated the pope by a manoeuvre which, serious as it was for Gregory, cannot fail to appeal to the sense of the ludicrous. The Genoese fleet conveying the prelates to Rome, most of them from France, Northern Italy, and Spain, was captured by Enzio, and the would-be councillors, numbering nearly one hundred and including Cardinal Otto, a papal legate, were taken to Naples and held in prison. In his letter of condolence to the imprisoned dignitaries the pope represents them as awaiting their sentence from the new Pharaoh. Brilliant as was the coup de main, it was destined to return to trouble the inventor. And the indignity heaped by Frederick upon the prelates was at a later time made a chief charge against him.
Gregory died in the summer of 1241, at an age greater than the age of Leo XIII. at that pope's death. But he died, as it were, with his armor on and with his face turned towards his imperial antagonist, whose army at the time lay within a few hours of the city. He had fought one of the most strenuous conflicts of the Middle Ages. To the last moment his intrepid courage remained unabated. A few weeks before his death he wrote, in sublime confidence in the papal prerogative: "Ye faithful, have trust in God and hear his dispensations with patience. The ship of Peter will for a while be driven through storms and between rocks, but soon, and at a time unexpected, it will rise again above the foaming billows and sail on unharmed, over the placid surface."
The Roman communion owes to Gregory IX. the collection of decretals which became a part of its statute book. He made the Inquisition a permanent institution and saw it enforced in the city of Rome. He accorded the honors of canonization to the founders of the mendicant orders, St. Francis of Assisi and Dominic of Spain.

§ 44. The First Council of Lyons and the Close of Frederick's Career. 1241 - 1250.

Gregory's successor, Coelestin IV., survived his election less than three weeks. A papal vacancy followed, lasting the unprecedented period of twenty months. The next pope, Innocent IV., a Genoese, was an expert in the canon law and proved himself to be more than the equal of Frederick in shrewdness and quickness of action. At his election the emperor is reported to have exclaimed that among the cardinals he had lost a friend and in the pope gained an enemy. Frederick refused to enter into negotiations looking to an agreement of peace until he should be released from the ban. Innocent was prepared to take up Gregory's conflict with great energy. All the weapons at the command of the papacy were brought into requisition: excommunication, the decree of a general council, deposition, the election of a rival emperor, and the active fomenting of rebellion in Frederick's dominions. Under this accumulation of burdens Frederick, like a giant, attempted to bear up, but in vain. All Western Christendom was about to be disturbed by the conflict. Innocent's first move was to out-general his antagonist by secretly leaving Rome. Alexander III. had set the precedent of delivering himself by flight. In the garb of a knight he reached Civita Vecchia, and there met by a Genoese galley proceeded to Genoa, where he was received with the ringing of bells and the acclamation, "Our soul is escaped like a bird out of the snare of the fowler." Joined by cardinals, he continued his journey to Lyons, which, though nominally a city of the empire, was by reason of its proximity to France a place of safe retreat.
The pope's policy proved to be a master stroke. A deep impression in his favor was made upon the Christian world by the sight of the supreme pontiff in exile. The division of European sentiment is shown by the method which a priest of Paris resorted to in publishing Innocent's sentence of excommunication against the emperor. "I am not ignorant," he said, "of the serious controversy and unquenchable hatred that has arisen between the emperor and the pope. I also know that one has done harm to the other, but which is the offender I do not know. Him, however, as far as my authority goes, I denounce and excommunicate, that is, the one who harms the other, whichever of the two it be, and I absolve the one which suffers under the injury which is so hurtful to the cause of Christendom."
Innocent was now free to convoke again the council which Frederick's forcible measures had prevented from assembling in Rome. It is known as the First Council of Lyons, or the Thirteenth Oecumenical Council, and met in Lyons, 1245. The measures the papal letter mentioned as calling for action were the provision of relief for the Holy Land and of resistance to the Mongols whose ravages had extended to Hungary, and the settlement of matters in dispute between the Apostolic see and the emperor. One hundred and forty prelates were present. With the exception of a few representatives from England and one or two bishops from Germany, the attendance was confined to ecclesiastics from Southern Europe. Baldwin, emperor of Constantinople, was there to plead his dismal cause. Frederick was represented by his able counsellor, Thaddeus of Suessa. Thaddeus promised for his master to restore Greece to the Roman communion and proceed to the Holy Land in person. Innocent rejected the promises as intended to deceive and to break up the council. The axe, he said, was laid at the root, and the stroke was not to be delayed. When Thaddeus offered the kings of England and France as sureties that the emperor would keep his promise, the pope sagaciously replied that in that case he would be in danger of having three princes to antagonize. Innocent was plainly master of the situation. The council was in sympathy with him. Many of its members had a grudge against Frederick for having been subjected to the outrage of capture and imprisonment by him.
At one of the first sessions the pope delivered a sermon from the text, "See, ye who pass this way, was ever sorrow like unto my sorrow?"  He dwelt upon five sorrows of the Church corresponding to the five wounds of Christ: the savage cruelty of the Mongols or Tartars, the schism of the Greeks, the growth of heresy, the desolation of Jerusalem, and the active persecution of the Church by the emperor. The charges against Frederick were sacrilege and heresy. As for the charge of heresy, Thaddeus maintained that it could be answered only by Frederick in person, and a delay of two weeks was granted that he might have time to appear. When he failed to appear, Innocent pronounced upon him the ban and declared him deposed from his throne. The deliverance set forth four grave offences; namely, the violation of his oath to keep peace with the Church, sacrilege in seizing the prelates on their way to the council, heresy, and withholding the tribute due from Sicily, a papal fief. Among the grounds for the charge of heresy were Frederick's contempt of the pope's prerogative of the keys, his treaty with the Sultan on his crusade, allowing the name of Mohammed to be publicly proclaimed day and night in the temple, having intercourse with Saracens, keeping eunuchs over his women, and giving his daughter in marriage to Battacius, an excommunicated prince. The words of the fell sentence ran as follows:
"Seeing that we, unworthy as we are, hold on earth the authority of our Lord Jesus Christ, who said to us in the person of St. Peter, 'whatsoever ye shall bind on earth,' etc., do hereby declare Frederick, who has rendered himself unworthy of the honors of sovereignty and for his crimes has been deposed from his throne by God, to be bound by his sins and cast off by the Lord and we do hereby sentence and depose him; and all who are in any way bound to him by an oath of allegiance we forever release and absolve from that oath; and by our apostolic authority, we strictly forbid any one obeying him. We decree that any who gives aid to him as emperor or king shall be excommunicated; and those in the empire on whom the selection of an emperor devolves, have full liberty to elect a successor in his place."
Thaddeus appealed from the decision to another council. His master Frederick, on hearing what was done, is said to have asked for his crown and to have placed it more firmly on his head. In vain did the king of France, meeting Innocent at Cluny, make a plea for the emperor, finding, as the English chronicler said, "but very little of that humility which he had hoped for in that servant of the servants of God." Frederick's manifesto in reply to the council's act was addressed to the king of England and other princes, and reminded them of the low birth of the prelates who set themselves up against lawful sovereigns, and denied the pope's temporal authority. He warned them that his fate was likely to be theirs and announced it as his purpose to fight against his oppressors. It had been his aim to recall the clergy from lives of luxury and the use of arms to apostolic simplicity of manners. When this summons was heeded, the world might expect again to see miracles as of old. True as these principles were, and bold and powerful as was their advocate, the time had not yet come for Europe to espouse them, and the character of Frederick was altogether too vulnerable to give moral weight to his words.
The council's discussions of measures looking to a new crusade did not have any immediate result. The clergy, besides being called upon to give a twentieth for three years, were instructed to see to it that wills contained bequests for the holy enterprise.
One of the interesting figures at the council was Robert Grosseteste, bishop of Lincoln, who protected against ecclesiastical abuses in England, such as the appointment of unworthy foreigners to benefices, and the exorbitant exactions for the papal exchequer. The pope gave no relief, and the English bishops were commanded to affix their seals confirming King John’s charter of tribute. The only notable achievement of the council of Lyons was the defeat of Frederick. Innocent followed it up with vigorous measures. Frederick's manifesto he answered with the reassertion of the most extravagant claims.
The bishop of Rome was intrusted with authority to judge kings. If, in the Old Testament, priests deposed unworthy monarchs, how much more right had the vicar of Christ so to do. Innocent stirred up the flames of rebellion in Sicily and through the mendicant orders fanned the fires of discontent in Germany. Papal legates practically usurped the government of the German Church from 1246 to 1254. In the conflict over the election of bishops to German dioceses, Innocent usually gained his point, and in the year 1247/1248 thirteen of his nominees were elected. At the pope's instigation Henry Raspe, landgrave of Thuringia, was chosen emperor, 1246, to replace Frederick, and at his death, a year later, William of Holland.
In Italy civil war broke out. Here the mendicant orders were also against him. He met the elements of revolt in the South and subdued them. Turning to the North, success was at first on his side but soon left him. One fatality followed another. Thaddeus of Suessa fell, 1248. Peter de Vinea, another shrewd counsellor, had abandoned his master. Enzio, the emperor's favorite son, was in prison. Utter defeat fell upon him before Parma and forced him to abandon all Lombardy. As if there had not been cursings enough, Innocent, in 1247, had once more launched the anathema against him. Frederick's career was at an end. He retired to Southern Italy, a broken man, and died near Lucera, an old Samnite town, Dec. 13, 1250. His tomb is at the side of the tomb of his parents in the cathedral of Palermo. He died absolved by the archbishop of Palermo and clothed in the garb of the Cistercians. Stupor mundi, the Wonder of the World, this is the title which Matthew Paris applies to Frederick II. Europe had not seen his equal as a ruler since the days of Charlemagne. For his wide outlook, the diversity of his gifts, and the vigor and versatility of his statecraft he is justly compared to the great rulers. Morally the inferior of his grandfather, Barbarossa, Frederick surpassed him in intellectual breadth and culture. He is the most conspicuous political figure of his own age and the most cosmopolitan of the Middle Ages. He was warrior, legislator, statesman, man of letters. He won concessions in the East and was the last Christian king of Jerusalem to enter his realm. He brought order out of confusion in Sicily and Southern Italy and substituted the uniform legislation of the Sicilian Constitutions for the irresponsible jurisdiction of ecclesiastical court and baron. It has been said he founded the system of centralized government and prepared the way for the monarchies of later times. He struck out a new path by appealing to the judgment of Christendom. With an enlightenment above his age, he gave toleration to Jew and Mohammedan. In his conflict with the pope, he was governed, not by animosity to the spiritual power, but by the determination to keep it within its own realm. In genuine ideal opposition to the hierarchy he went farther than any of his predecessors. Dollinger pronounced him the greatest and most dangerous foe the papacy ever had. Gregory and Innocent IV. called him "the great dragon" and declared he deserved the fate of Absalom. And yet he did not resort to his grandfather's measures and set up an anti-pope. Perhaps he refrained from so doing in sheer disdain. It has been surmised that Frederick was not a Christian. Gregory charged him specifically with blasphemy. But Frederick as specifically disavowed the charge of making Christ an impostor, and swore fealty to the orthodox faith. If he actually threw off the statement of the three impostors as charged, it must be regarded as the intemperate expression of a mood. Neander expresses the judgment that Frederick denied revealed religion. Schlosser withholds from him all religious and moral faith. Ranke and Freeman leave the question of his religious faith an open one. Hergenrother makes the distinction that as a man he was an unbeliever, as a monarch a strict Catholic. Gregorovius holds that he cherished convictions as sincerely catholic as those professed by the Ghibelline Dante. Fisher emphasizes his singular detachment from the current superstitious of his day. Huillard-Breholles advances the novel theory that his movement was an attempt to usurp the sovereign pontificate and found a lay papacy and to combine in himself royalty and papal functions.
Frederick was highly educated, a friend of art and learning. He was familiar with Greek, Latin, German, French, and Arabic, as well as Italian. He founded the University of Naples. He was a precursor of the Renaissance and was himself given to rhyming. He wrote a book on falconry. It was characteristic of the man that while he was besieging Milan in 1239, he was sending orders back to Sicily concerning his forests and household concerns, thus reminding us of Napoleon and his care for his capital while on his Russian and other campaigns. Like other men of the age, he cultivated astrology. Michael Scott was his favorite astrologer. To these worthy traits, Frederick added the luxurious habits and apparently the cruelty of an Oriental despot. Inheriting the island of which the Saracens had once been masters, he showed them favor and did not hesitate to appropriate some of their customs. He surrounded himself with a Saracenic bodyguard and kept a harem.
Freeman's judgment must be regarded as extravagant when he says that "in mere genius, in mere accomplishments, Frederick was surely the greatest prince that ever wore a crown." Bryce pronounces him "one of the greatest personages in history." Gregorovius declares that, with all his faults he was the most complete and gifted character of his century." Dante, a half-century after his death, puts the great emperor among the heresiarchs in hell. When the news of his death reached Innocent IV., that pontiff wrote to the Sicilians that heaven and hell rejoiced at it. A juster feeling was expressed by the Freiburger Chronicle when it said, "If he had loved his soul, who would have been his equal?"

§ 45. The Last of the Hohenstaufen.

The death of Frederick did not satisfy the papacy. It had decreed the ruin of the house of the Hohenstaufen. The popes denounced its surviving representatives as "the viperous brood" and, "the poisonous brood of a dragon of poisonous race."
In his will, Frederick bade his son Conrad accord to the Church her just rights and to restore any he himself might have unjustly seized but on condition that she, as a merciful and pious mother, acknowledge the rights of the empire. His illegitimate son, the brilliant and princely Manfred, he appointed his representative in Italy during Conradin's absence.
Innocent broke up from Lyons in 1251, little dreaming that, a half century later, the papacy would remove there to pass an exile of seventy years. After an absence of six years, he entered Rome, 1253. The war against Frederick he continued by offering the crown of Sicily to Edmund, son of the English Henry III. Conrad descended to Italy and entered Naples, making good his claim to his ancestral crown. But the pope met him with the sentence of excommunication. Death, which seemed to be in league with the papacy against the ill-fated German house, claimed Conrad in 1254 at the age of 26. He left an only son, Conradin, then two years old.
On the youthful Conradin, grandson of Frederick II., the hopes of the proud German house now hung. Conradin marched to Italy to assert his rights, 1267, was met by the papal ban, and, although received by popular enthusiasm even in Rome, he was no match for the tried skill of Charles of Anjou. His fortunes were shattered on the battlefield of Tagliacozzo, Aug. 23, 1268. Taken prisoner, he was given a mock trial. The Bolognese lawyer, Guido of Suzarra, made an ineffective plea that the young prince had come to Italy, not as a robber but to claim his inheritance. The majority of the judges were against the death penalty, but the spirit of Charles knew no clemency, and at his instance Conradin was executed at Naples, Oct. 29, 1268. The last words that fell from his lips, as he kneeled for the fatal stroke, were words of attachment to his mother, "O mother, what pain of heart do I make for you!"
With Conradin the male line of the Hohenstaufen became extinct. Its tragic end was enacted on the soil which had always been so fatal to the German rulers. Barbarossa again and again met defeat there; and in Southern Italy Henry VI., Frederick II., Conrad, Manfred, and Conradin were all laid in premature graves.
At Conradin's burial Charles accorded military honors, but not religious rites. The Roman crozier had triumphed over the German eagle. The Swabian hill, on which the proud castle of the Hohenstaufen once stood, looks down in solemn silence upon the peaceful fields of Wurttemberg and preaches the eloquent sermon that "all flesh is as grass and all the glory of man is as the flower of grass." The colossal claims of the papacy survived the blows struck again and again by this imperial family, through a century. Italy had been exposed for three generations and more to the sword, rapine, and urban strife. Europe was weary of the conflict. The German minnesingers and the chroniclers of England and the Continent were giving expression to the deep unrest. Partly as a result of the distraction bordering on anarchy, the Mongols were threatening to burst through the gates of Eastern Germany. It was an eventful time.
In the mighty duel which has been called by the last great Roman historian (Gregorovius) the grandest spectacle of the ages, the empire had been humbled to the dust. But ideas survive, and the principle of the sovereign right of the civil power within its own sphere has won its way in one form or another among European peoples and their descendants. And the fate of young Conradin was not forgotten. Three centuries later it played its part in the memories of the German nation, and through the pictures of his execution distributed in Martin Luther's writings contributed to strengthen the hand of the Protestant Reformer in his struggle with the papacy, which did not fail.

- History of the Christian Church
by Philip Schaff

Principum mundi maximus, stupor quoque mundi et immutator mirabilis, "greatest of the princes of the earth, the wonder of the world and the marvellous regulating genius [innovator] in its affairs." Luard’s M. Paris, V. 190, 196. In his letters Frederick styled himself Fredericus Dei gratia Romanorum imperator et semper augustus, Jerusalem et Siciliae rex.