The title is explained at the beginning (p. 1) and end (p. 226) of Rosamond McKitterick's new book, but invention does not appear much in between. McKitterick intends the word in the Latin sense. For her, the anonymous authors of the unique collection of popes’ biographies which scholars have called the Liber pontificalis since 1886 (when volume i of Duchesne's magisterial edition appeared) decisively shaped what readers, and everyone else, came to expect the papacy to be. In other terms, shadowy early medieval Lateran functionaries taught the rest of Europe, and then the world, to consider the bishop of Rome heir to the city's imperial heritage and a peerless authority on Christian doctrine, law and liturgy. For McKitterick, the Liber pontificalis also contributed key elements to medieval Europe's understanding of Rome as a Christian metropolis. This is the vast ‘power of the text’ to which McKitterick refers often (pp. xi, 1, 29, 36, 171). Despite her many illuminating comments on what one might call the ‘power of the early medieval readers’ who manipulated the Liber to suit their ends and, overall, proved unreceptive (there are few surviving manuscripts) to what the Liber’s pontificators had to say, McKitterick thinks multiple unrelated authors sustained an unwavering, supremely confident view of what their writing would achieve over the roughly 350 years (mid-sixth to late ninth centuries) during which the series of biographies was compiled, edited and updated.

Rome and the invention of the papacy emerges from a series of lectures delivered in Dublin in 2018, and a preceding decade of teaching at Cambridge that involved several ‘field trips’ to Rome. Associated periods of research there and in Ravenna and, perhaps most important, journeys to inspect all the known manuscripts of the Liber written before 1000 (p. 173), further contribute to the great erudition in McKitterick's pages. The prose is clear and plain; the continuous summarising of what has been said and foreshadowing of what is about to be said probably reflects the author's effort to tie together components of a volume she wrote (and delivered) in instalments.

The book is divided into six chapters, plus conclusion. The first outlines McKitterick's view on the Liber’s ‘text and context’ (notice the singular, significant for what remained essentially an ‘open text’ from the sixth century on). Chapter ii astutely reconstructs how the Liber Christianised early first millennium Roman history, and the city's inhabitants, while portraying the bishops as the city's tireless leaders. Then McKitterick turns attention onto how the Liber’s interest in ‘apostolic succession’ created the impression of a solicitous group of Peter-imitators ceaselessly caring for Rome and Christian orthodoxy, from the beginning, and thereby also a new ‘identity’ for Roman Christianity. The fourth chapter instead analyses papal evergetism and its representation in the Liber. In chapter v the author returns to the leadership of Rome's bishops, and how the Liber depicts their contribution to Christian liturgy and law, thereby making a claim about their universal authority. After so much on the production of the Liber, McKitterick addresses the text's consumption in chapter vi, about the manuscript evidence and the text's early medieval reception in Italy and Europe. This outstanding section of the book reveals how uninterested readers were in pontificates after 757, how many radically different versions of the Liber circulated, how scribes adapted the text to their purposes and intended audiences, and how huge a role the Carolingian court and its satellites in the last decades of the eighth century played in its dissemination. McKitterick's achievement is to demonstrate that the collated, seamless Duchesne text familiar today is a very different Liber from those people read before 1000. Yet precisely the multifarious manuscript versions created outside the Lateran make one wonder whether the Liber really advanced a ‘comprehensive … historical argument’ (p. 31), and exhibits ‘consistency’ of form (pp. 13, 71) and one ‘overall purpose’ (p. 225).

McKitterick is an insightful contextualiser of the Liber's creation in the sixth and seventh centuries (the composition and circulation of post-715 biographies receive less attention in her book). Her study carefully sets its first redaction in the context of the opening Gothic Wars and contentious papal elections just decades earlier. She also sees the popes’ desire to assert doctrinal and political autonomy from Constantinople as the leitmotif in the later sixth- and seventh-century continuations of the Liber.

In a history book about the assembly and reception of another history book, textuality naturally takes precedence. McKitterick delves beyond the usually-listed sources for the Liber (like Suetonius’ Historia Augusta, Eusebius, Jerome's On illustrious men) to highlight its affinities with such unexpected texts as Cicero's On the republic, Strabo's Geography, the Roman martyrial Acts, Byzantine polemical writings, various sections of the New Testament, and a seventh-century Coptic history of Alexandria's patriarchate. Deep knowledge of first millennium historiography thus enriches her discussion. A subtle and penetrating interpreter of historical texts, McKitterick is perfectly aware of the ‘problem’ (p. 36) in having the subject of a representation of reality participate in that representation's creation as text. Nevertheless, she trusts those subjects and their representations more than a cynic would.

Arguably, such reliance on what texts say can also be a limitation, and material culture might be a more reliable guide to the papacy's rise than the text that ‘invented’ that rise. For instance, McKitterick's analysis of all the building that the Liber claimed the popes did tends to accept what the Lateran writers said, subordinating to the text's lush presentation of papal patronage the archaeological evidence (well summarised in Dey's 2021 The making of medieval Rome). The Liber ‘cannot be regarded simply as propaganda’ (p. 123), even when inscriptions or other material evidence suggest that papal ‘monopoly’ on postclassical construction in Rome is an ‘illusion’ (p. 60) wilfully manufactured in the Lateran. The marginalisation of Byzantine authority and patronage in the postclassical city throughout Rome and the invention of the papacy is likewise related to the book's deference to the Liber's maximalist presentation of papal authority. Both run against recent scholarly interpretation, which attempted to de-papalise early medieval Roman history by relying less on the Liber's account and more on the archaeological record.

Probably alluding to Duchesne's fulsome and meaty text, rather than to the partial, abbreviated lists of popes that actually circulated in the early Middle Ages, McKitterick notes that Liber ‘enchanted readers with a vision of Rome’ (p. 38). Among the enchanted she surely includes herself. Her acute study of the genesis and spread of the Liber pontificalis is a tribute to the enduring enchantment.