Pope Alexander II’s successor, by acclamation of clergy and people, was Archdeacon Hildebrand, who took the name of Gregory VII (1073-1085) in memory of his mentor Gregory VI and in honour of Gregory the Great, whose writings strongly influenced him. He would prove to be one of the most significant and controversial of popes. We know his policies from the decrees of the twice-yearly synods, held during Lent and in November, but also from 390 letters. He is the only pope in the period 882 to 1198 whose register, the official collection of a pope’s correspondence, has survived.

It includes a text headed Dictatus Papae (Dictation of the Pope), a list of twenty-seven propositions by the pope himself, drawn up in 1075. Although not an official decree, it reveals Gregory’s ideals and something of his ‘demonic zeal’ in promoting them. Several of the propositions stated long-accepted papal rights, such as those of hearing appeals and judging all major cases. More novel were the theses that only the pope ‘can use imperial insignia’ and that ‘all princes kiss the feet of the pope alone.’ So too were the claims that he ‘is permitted to depose emperors’ and ‘can absolve subjects from fealty to the wicked.’ These derived from recent discussions in the papal circle over the conflict in Milan, and a search for such historical precedents as Pope Zacharias’ role in the deposing of the Merovingian dynasty in 751. These claims would be put to the test before a year was out.

Gregory did not inform Henry IV of his election, but the king was facing a serious revolt in Saxony and at first was keen to mend fences with the new pope, at least until the revolt was crushed in October 1075. After that he ignored papal protests, appointed Italian bishops on his own authority and called a synod of German and northern Italian bishops to meet at Worms on 24 January 1076. Here both king and episcopate denounced Gregory VII for interfering in their affairs and denying them their rights. The twenty-six bishops renounced allegiance to him, claiming he had broken a promise not to seek election to the papacy and was committing adultery with Countess Matilda of Tuscany. They complained that ‘all judgements and decrees are enacted by women in the Apostolic See, and ultimately the whole orb of the Church is administered by this new senate of women’ and that Gregory called his fellow bishops ‘sons of whores and other names of this sort’.

Their letters arrived before the opening of the Lenten synod in Rome in February, at which Gregory composed his reply: By virtue of the power ‘given to me from God of binding and loosing in heaven and on earth . . . I deny to King Henry, son of the emperor Henry, who has risen with unheard-of pride against your church, the government of the entire kingdom of the Germans and of Italy, and I absolve all Christians from the bond of any oath that they have taken, or shall take, to him; and I forbid anyone to serve him as king.’ Henry and all the bishops who had written with him were declared excommunicate.

The king could not use force against the pope, and all hinged on whether or not Gregory’s sentence on Henry would have any practical effect. To make it work, the pope resorted to the tactic he used to enforce his ecclesiastical judgements, sending copies of his decree to as many interested parties as he could reach, to make it as widely known as possible. Thus, when an archbishop was excommunicated, the pope ensured that all his suffragan bishops were informed, as the papal decision justified their defying the metropolitan.

In this case the king’s weak political position in Germany proved crucial, as the Saxon aristocracy used the papal decree to justify renewing their revolt, since it invalidated their earlier submission to the king. Other discontented magnates were equally keen to use the papal ban to justify disregarding their oaths of fealty. Many German bishops, however resentful of Gregory’s conduct, felt unable to reject papal authority and accepted his sentence.

So, in the course of 1076 Henry’s position in Germany crumbled, while he could not coerce Gregory, who was backed by Matilda of Tuscany, the heiress of the Margrave Boniface and the wealthiest and most powerful lay magnate in northern Italy. The king attempted a spiritual riposte, asking his bishops to excommunicate Gregory VII. Only one of them would agree to do so, and he died suddenly a few weeks later, making it appear God favoured the pope.

By 16 October, when Henry met the German princes, his position had become untenable. They demanded that he get the excommunication lifted within six months or they would feel freed from their previous oaths of loyalty to him. They also invited Gregory VII to come and meet them at Augsburg in February 1077 to mediate in their disputes with the king. It was while on his way to this meeting that the pope was intercepted by King Henry at Countess Matilda’s castle at Canossa in January 1077.

The road to Canossa was in many ways a short one. The conflict that produced Henry’s submission was of recent origin, as were the papal reform party itself and the king’s political difficulties in Germany. But the new relationship between pope and German ruler, consisting largely of friction, distrust and periodic conflict, would last for centuries to come. The traditions of more harmonious papal-imperial relations that characterised the preceding millennium effectively withered and died when the papacy ceased to be an essentially Roman institution with wider aspirations and tried instead to become a universal one with Roman connections.

The transformation in the nature of the papacy in this period reflects wider changes taking place in Western Europe. The ideal of a common Christian society of shared beliefs and culture needed an institutional structure that could no longer be provided by the emperors. In the West, the imperial office had been confined to the rulers of Germany since the mid-tenth century and was little more than a constitutional pretext for their fragile rule over its regional duchies and the overlordship of various Slav states beyond its eastern frontier. Whatever respect was accorded his title, the emperor had no authority over the other Western kingdoms and never tried to claim it. The only institution with ideologically grounded and widely accepted claims to superiority over all secular rulers was the papacy.

In political terms Canossa was less of a victory for Gregory VII than it might appear, and this may explain his reluctance to accept the royal submission. Having lifted the excommunication, the pope deprived Henry’s enemies in Germany of their excuse for continued resistance, and they were less willing to rely on papal support in the future, preferring instead to elect a new king, Rudolf of Rheinfelden, in March 1077.

By 1080 Henry was able to disregard almost all the undertakings he had made to the pope at Canossa, and Gregory excommunicated him again at a synod. The impact was far weaker a second time, and on 25 June a group of twenty-seven bishops and a cardinal loyal to Henry met at Brixen in northern Italy and deposed ‘the pseudo-monk Hildebrand known as Gregory VII’ on charges ranging from heresy and sacrilege to arson and including claims that ‘he is an open devotee of divinations and dreams, and a necromancer working with an oracular spirit.’ He was also accused of murdering four previous popes, including Alexander II, and of being devoted to ‘obscene theatrical shows’. Having recorded these crimes with considerable relish, the bishops elected Archbishop Wibert of Ravenna as pope. He took the name of Clement III in honour of the first German pope, Clement II.

As with earlier schisms, this conflict produced a flurry of historical research into earlier papal texts supporting the claims of one side or the other, and the invention of new ones when required. Thus in the 1080s lawyers working for Clement III forged a decree of the obscure Pope Leo VIII (963-965), stating that it was the emperor who made the pope. Around 1085 an Italian bishop driven into exile by the reformers wrote to Henry IV to show that the Liber Pontificalis proved that bishops and popes should be appointed by kings and emperors. He further cited Otto III’s mutilation of ‘a certain false pope’ (John XVI) and Henry II sitting in judgement on three papal claimants at Sutri in 1046. Biblical exegesis was also used to comment on the current crisis, particularly by a circle of writers patronised by Matilda of Tuscany.

In 1080 Henry killed the ‘anti-king’ Rudolf, enabling him to intervene more effectively in Italy. In March 1084 he and his army entered Rome, while Gregory VII took refuge in the Castel Sant’Angelo. Clement III was formally elected pope by the Roman clergy and people, and then crowned Henry emperor. But in May the approach of Gregory’s Norman allies, led by Robert Guiscard, made Henry and his antipope withdraw. The Normans sacked Rome and massacred those who resisted, an episode long remembered. Evidence of the destruction has been found on the Caelian where the basilicas of San Clemente and the Quattro Sancti Coronati were burned down. In consequence Gregory himself was expelled by the infuriated populace when the Normans departed and took refuge with them in the south, dying in May 1085. He was canonised by Paul V in 1606.

Related to Gregory’s attempt to create a new order within Christian society under papal leadership was his concern for its defence against external enemies. During the unstable period that followed the ending of the Macedonian dynasty in 1057, the Eastern empire was threatened by the Seljuk Turks. After their decisive defeat of the emperor Romanus IV (1068-1071) at the battle of Manzikert in 1071, Seljuk warlords overran Asia Minor and carved out new states for themselves. Unable to replace the army lost at Manzikert, the emperor Michael VII (1071-1078) asked the pope to secure military aid from the West, promising a restoration of relations between Rome and Constantinople on papal terms.

On 1 March 1074 Gregory issued a general letter ‘to all who are willing to defend the Christian faith’, stating that ‘a race of pagans has strongly prevailed against the Christian empire . . . it has slaughtered like cattle many thousands of Christians.’ In a private letter to Matilda of Tuscany, he said he intended to lead the expedition in person, although expecting it would result in his martyrdom. Later the same year he told King Henry IV that he hoped to form an army 50,000 strong and hinted that the Church of the Holy Sepulchre in Jerusalem would be its destination. In practice, this expedition hardly made it onto the drawing board, any more than did a proposal by the French Count Ebles de Roucy to raise an army to fight against the Muslims in Spain, which Gregory backed in 1073. His predecessor, Alexander II, may have sanctioned what in retrospect has been seen as the prototype crusade: a similar French expedition in 1064 that crossed the Pyrenees to take the fortress of Barbastro in Aragón, only to lose it again the next year.

Where Gregory had more success in the Iberian peninsula was in trying to suppress the Mozarabic liturgy, the distinctive liturgical tradition of the church in Spain, whose texts, music and ritual distinguished it from Roman and Frankish equivalents. The pope relied upon a mythical tale of a visit to Spain by seven bishops, supposedly sent by Peter and Paul themselves, to claim that ‘it is sufficiently clear how great a concord Spain enjoyed with the city of Rome in religion and the ordering of the divine office.’ But this uniformity in faith and worship, he argued, had been broken firstly by the spread of heresy and then by the conquest of Spain by the Goths and subsequently by the Arabs. In 1074 he demanded of King Alfonso VI of Castile (1072-1109) that he and the church in his kingdom ‘recognise the Roman church as truly your mother . . . and that you receive the order and office of the Roman church, not of the Toledan or any other, but that like the other kingdoms of the west and north, you hold to that which has been founded through Christ by Peter and Paul upon the firm rock and consecrated by their blood, against which the gates of hell, that is the tongues of heretics, have never been able to prevail.’

Despite argument and prevarication by both the monarch and his bishops, the Mozarabic liturgy was formally renounced at a synod held in Burgos in 1087 and replaced by the papally approved service books, which, however, were not purely Roman in origin but contained a strong admixture of Frankish elements. In reality the papal view that there had once been a uniform Latin liturgy of Roman origin used by all the churches of the West and that local variants, such as the Spanish Mozarabic rite or the Ambrosian one followed in Milan, were deviations caused by loss of communication with Rome was entirely mistaken.

Gregory’s death in Salerno in May 1085 left his supporters divided, and only a year later could they agree on a successor, the Lombard aristocrat Desiderius, abbot of the great monastery of Monte Cassino since 1058. Taking the name of Victor III, he was opposed not only by the antipope Clement III but also by the more uncompromising followers of Gregory, since he had once tried to broker a compromise with Henry IV. Victor was driven from Rome four days after his election by popular rioting, and withdrew to Monte Cassino, refusing to function as pope until reconfirmed by a synod of bishops meeting at Capua in March 1087. Two months later his supporters led by the Norman prince of Capua and Countess Matilda of Tuscany seized control of the Leonine City, the fortified area around St. Peter’s, where he was finally consecrated on May 9. Although the antipope was expelled from Rome in June, Victor spent most of his short pontificate in Monte Cassino, dying there on 16 September.

By this time Clement III had regained Rome, and it was not until March 1088 that the reform party was able to meet at Terracina, to elect Odo de Châtillon, who became Urban II (1088-1099). A French aristocrat and former monk of Cluny, he had been made cardinal bishop of Ostia by Gregory VII in 1080 and papal legate in Germany in 1084. He was an unwavering Gregorian, writing ‘in all things trust and believe in me as in my blessed lord Pope Gregory,’ and thus could reconcile those who had refused obedience to Victor III. He reconfirmed the reform programme through the decrees of a synod he held at Melfi under Norman protection in 1089.

Control of Rome continued to fluctuate, with Urban having to abandon the city to Henry IV and Clement III in 1090 to take refuge again with the Normans. He regained part of the city in 1093 and was triumphantly reinstalled by the army of the bellicose Matilda of Tuscany (whose armour was preserved as late as the seventeenth century) in 1096, but Clement III did not lose his last hold on Rome until 1098, when the Castel Sant’Angelo fell. Clement withdrew to his archbishopric of Ravenna, where he died in September 1100.

Just as Urban’s position in Rome gradually improved throughout the 1090s so did his wider standing in Western Christendom. Compromise was necessary to bring this about, something Gregory VII would never have contemplated. No reconciliation proved possible with Henry IV, but papal relations with France recovered from threats by Gregory VII to excommunicate its king Philip I for marrying a near relative. In England Urban had to concede in 1095 that his legates would only enter the kingdom with royal consent, and he was unable to persuade King William II (1087-1100) to admit Anselm, his appointee as archbishop of Canterbury. Papal involvement in Spain was more warmly welcomed, following Alfonso VI of Castile’s conquest of Toledo in 1085 and the reinstatement of its archbishopric as the primatial see for all the Iberian Peninsula by Urban II in 1088.

The principles of the reform programme, especially the removal of lay involvement in the selecting and investing of bishops, continued to be reiterated, particularly at the council Urban held at Clermont in 1095 and in his last synod in Rome in 1099. Such decrees did not provoke the frequent confrontations that had marked the pontificate of Gregory VII, not least because Urban had other more urgent objectives, notably his aim to persuade Christians in the West to join in an expedition to Jerusalem.

The loss of Urban II’s letters and the text of the sermon he preached at the opening of the Council of Clermont in November 1095 make it impossible to know how he presented the objectives of what became the First Crusade. The Eastern emperor Alexius I (1081-1118), founder of the Comnenian dynasty, had sent envoys to the pope earlier in 1095, asking him to raise military aid from the West for his campaigns against the still expanding Seljuks in Asia Minor. However, following the lead of Gregory VII in his plan to march to the Church of the Holy Sepulchre, Urban focussed instead on calling for an expedition to restore Christian rule over Jerusalem. And two weeks before he died, it was achieved.