Apologetics take their place beside miracles of healing and courage in the face of persecution as an important means of furthering the early Christian mission. In the first two centuries AD, when the popular perception was that Christianity was closely allied to Judaism, the argument from Old Testament prophecy was important. In the third century, however, as the Church gained ground among the educated classes in east and west, the emphasis changed to an attempt to demonstrate the superiority of Christianity over its pagan rivals as a philosophy with a more convincing understanding of the role of providence. Apologists in the north African tradition, Tertullian, Minucius Felix, Arnobius and Lactantius, all played their part in this process. The prophecies of the Old Testament had to be confirmed by other prophecies, notably the Sibylline oracles and the sayings of Hermes Trismegistus. Finally, in the fourth century, many north Africans who, like Augustine for ten years, adhered to Manichaean Christianity relied wholly on these authorities, rejecting the Old Testament altogether.

Abelard discussed the status and history of the ordo sanctimonialium in several of his works. In them he identified abbesses as the successors to the ancient order of deaconesses and thus sacramentally ordained and equal to any male order. This understanding followed a venerable tradition that stood in stark contrast to the more recent claims of the Glossa ordinaria, Gratian and Peter the Lombard that the only true sacramental orders were the subdiaconate, the diaconate and the presbyterate. Abelard's work then can be understood in part as a response to these claims and a defence of the older tradition.

When it first appeared in Germany, Gottfried Arnold's History of heretics (1699) was a publishing sensation, immediately causing a stir due to its radical reinterpretation of the Christian past. Numerous scholars wrote against it, but the most determined was the Orthodox Lutheran Ernst Salomon Cyprian, who considered the central thesis of the work – that the history of the Christian Church was a history of decline – a deliberate attack on the principles of Lutheran belief. In Cyprian's view, Arnold's reading of the past was shaped by a cast of personal faith which not only rewrote the Protestant narrative of Christian history, but threatened the very fabric of Lutheran belief.

In the newly independent Irish Free State, a triumphalist Catholicism was embodied visually in mass-produced imagery and revivalist architecture. The Academy of Christian Art was set up in 1929 to regenerate Catholic art and architecture, but it failed to address the challenge of Modernism. A debate between eclectic and modern form was most acute in architecture, where the Hiberno-Romanesque and the neo-Classical were favoured by lay and cleric alike. Stained glass was the one form where Modernism was influential. The culmination of populist Catholicism and its visual representation was the Eucharistic Congress of 1932 with its temporary public altars and massive spectacle: a manifestation of Irish national identity.

Peter the Chanter (d. 1197) was arguably the foremost theologian at the Paris of his day. Envisaging the house of theology as composed of lecturing, disputing and preaching, he himself was the first to compose lectiones on all the books of the Bible; his questiones were collected in a large Summa de sacramentis; and although few of his sermons have survived, he wrote a popular manual of moral theology for preachers, the Verbum abbreviatum (VA), that has survived in nearly a hundred manuscripts across western Europe. The VA was the first of the Chanter's works to be published, in 1639 by the Belgian monk Georges Galopin in a serviceable edition from three northern French manuscripts. It was given wide circulation when abbé Migne republished it in the Patrologia Latina in 1855. In 1905 Camille Miroux was the first to recognise that the VA had survived in two versions, a long one in six manuscripts and a short one in at least forty manuscripts that became the vulgate version and was that edited by Galopin. In a Handschrift Reise in 1959 I examined seventy-three of the eighty-five manuscripts known to me and published my findings, classifications and conclusions in Masters, princes and merchants. Galopin had also found a fragment of the long version which he published as an appendix to his own edition. Although it is futile to determine how many have consulted this fragment in Migne's reprint, to my knowledge I am the only one who has printed extracts from the complete long version.