What’s in a Pope’s Name?

Pope Francis’ choice of his official name in 2013 ruffled a few feathers. That he was the first pope to adopt it was not the only reason. In 1210, Pope Innocent III (1198-1216), that shrewdest of operators, decided to promote, rather than suppress, the mendicant order recently founded by Francis. Eight centuries on, St Francis’ uncompromising espousal of the vita apostolica still has unsettling resonances for some. Finding myself within inches of his habit at the recent National Gallery exhibition on the Franciscans could not but prompt awed reflection.

Pope Francis’ successor more conventionally chose a well-worn papal name, becoming Leo XIV. He explained in a brief video that ‘there are different reasons for this, but mainly because Pope Leo XIII in his historic encyclical Rerum novarum addressed the social question in the context of the first industrial revolution’. In the encyclical, issued in 1891, Leo XIII (1878-1903) addressed the challenges generated by industrial capitalism, particularly with respect to workers. Heavily indebted to St Thomas Aquinas, he developed an impressively sophisticated analysis. According to Leo XIV, we are now undergoing a second economic transformation of similar magnitude, in the shape of technology, particularly AI. This poses commensurate challenges to human dignity, to which the Church must respond.

The pope highlighting this reason for his choosing the name Leo provoked widespread comment, as any mention of AI currently does. It has been little noticed that he opens by saying that there are others, too. Which of the 12 previous popes Leo might he have had in mind?

It seems unlikely that either Leo XII (1823-9), who prohibited Jews from owning property in the Papal State, or Leo X (1513-21), whose sale of indulgences to fund the rebuilding a St Peter’s Basilica so outraged Martin Luther, have appealed to Leo XIV. I suggest that he might instead have been thinking of three far earlier Leos.

Leo IX (1049-54) refused to accept election at Worms under Emperor Henry III’s aegis, and insisted on travelling to Rome, dressed as a pilgrim, for a canonical election. He was accompanied for part of the way by a monk called Hildebrand, the future Gregory VII (1073-85). Leo initiated the programme later consummated by Gregory: to protect the clergy from secular pollution by bearing down on nicolaitism (priestly marriage) and simony (sale of clerical office). He did so by summoning bishops from throughout Christendom to reforming synods over which he presided. They were no longer restricted to the Roman ecclesiastical province and imperial territories; their decrees were universally binding.

Leo III’s (795-816) crowning of Charlemagne, king of the Franks, as Roman Emperor in St Peter’s on Christmas Day 800 became the epochal event in medieval Western European history. Although the pope was at that point being protected by Charlemagne, this coronation set the stage for later assertion of the papal right to dispose of Roman imperial office. Leo’s commissioning of a mosaic in the Lateran Palace, depicting St Peter investing him with keys and Charlemagne with a banner, suggests that he anticipated the ceremony’s eventual significance. The pope’s unique plenitudo potestatis (fullness of power) would be extended over lesser Christian rulers too. This papal monarchy would survive until the Reformation.

Every subsequent Pope Leo must have been conscious that he could never match Leo I (440-61). Like many late antique popes, Leo was a Roman lawyer. It was he who first defined with juristic precision the pope’s role as St Peter’s vicar. Each pope was deemed to inherit, in a strictly legal sense, direct from Peter the judicial powers of binding and loosing on Earth and in heaven that, according to Matthew’s Gospel, Christ had given Peter. The papal office was to be Peter in this sense, the rock on which the Church was founded, ‘unworthy’ though each heir must be in a personal sense. Hence Leo’s repeatedly speaking in the voice of Peter, who had come to Rome as the most propitious location for spreading the Gospel. In 410, Leo had witnessed the sacking of Rome by the Goths. In 452, as pope, he persuaded Attila ‘the Hun’ to spare the city. In his ‘Tome’ – a letter addressed to Flavian, patriarch of Constantinople, in response to an appeal – Leo formulated what became a definitive analysis of Christ’s Incarnation.

All three of these early Leos in their different ways pointed to very significant developments in the deployment of papal power to change the world. Leo I defined that power. Leo III’s demarche created the basis for the papal monarchical claims which would dominate Western Christendom during the high Middle Ages. Leo IX’s quest to restore pristine purity marked a very significant step in the centralisation of papal control over Western churches, and the imposition on them of his agenda. Given that Leo XIII was the first pope for 1600 years not to rule a papal state, and that the modern Holy See regards the loss of that territory in the 19th century as a providential liberation from temporal distractions, it seems unlikely that the Holy Spirit had Leo III particularly in mind when it inspired Cardinal Prevost to select his official name. But Leos I and IX would suggest that it was concerned with the maintenance of the pope’s unique office, with the use of that office to lead and cleanse Christendom, and (in Leo I’s case) with having the courage to confront secular power, if not to assert control over it. Leo XIV has already received Vice-President Vance and telephoned President Putin.

These matters are likely to be every bit as important to Leo XIV as the new threat posed by AI. Without them, he knows that he would not be capable of addressing that threat. He embodies the oldest institution in the world. He must take the long view.


George Garnett is Professor of Medieval History and Fellow of St Hugh’s College at Oxford University.