Erik Thunø’s The Apse Mosaic in Early Medieval Rome: Time, Network, and Repetition presents an alternative “non-diachronic” art-historical interpretation of Roman apse decoration from the sixth through ninth centuries. He identifies a core set of examples that share key visual and textual features, including: SS. Cosmas and Damian (526–30); S. Agnese (625–38); S. Venanzio (640–42); the apses of Paschal I (817–24)—S. Prassede, S. Cecelia, S. Maria in Domnica; and S. Marco (827–44). While he believes that scholarship to date has produced compelling studies of the individual monuments, Thunø chooses to deliberately ignore, disregard, and overlook (his terms) various disciplinary assumptions that he feels have limited alternative and comprehensive approaches to these works. Thunø’s main position is that “the conception and duration of the repetitive apsidal formula” (13) evinced in their decorative programs is neither a product of iconographic stagnation nor the medieval penchant for quoting venerable exemplars. Rather, he promotes the continuity of imagery as a “synchronic” manifestation, which reflects a timeless ecclesiological essence, aligning heaven and earth in what he terms a visual communio sanctorum. Despite his zeitgeistlich stance, Thunø is not entirely able to divorce his discussion from causality and agency, as he recognizes the phenomenon in terms of papal policy and the growth of post-apostolic relic veneration in early medieval Rome. The reader is certainly presented with a fresh and compelling means of understanding apse programs of this period. Still, and despite his explanatory remarks, it is somewhat ironic that Thunø’s truncated historical analysis serves his overall interpretation.

In chapter 1, Thunø presents a straightforward iconographic description of early medieval apse decoration in an attempt to define a characteristic visual identity for his examples. He traces the evolution of medieval decoration from the early Christian apses of Rome—specifically the centrally convergent traditio legis type depicting Christ flanked by two or more apostles, such as the late fourth-century apse at Santa Pudenziana. In Thunø’s scheme, it is the addition of post-apostolic saints and the papal donor—first seen in the apse of SS. Cosmas and Damian—that mark a significant shift. Culling much information from his earlier studies, Thunø includes in his criteria the appearance of texts, most often gold on blue mosaic, that describe the basic visual elements of the apses (papal donor, titular saints) and their aesthetics of light and material splendor. In compiling his “control group,” Thunø surveys additional monuments in Rome that are no longer extant, partially preserved, or heavily restored. While this exploration reveals continuities, Thunø admits that exceptions abound. He states, however, that “even if the formula was not always applied equally rigorously” (58), the essential elements were maintained. At the same time, this pretense is not entirely sustainable. The replacement of the figure of Christ for a representation of the saint in the apse of S. Agnese, for instance, cannot be fully explained within his perceived standardization of imagery and content.

Though his study focuses on Rome, Thunø’s brief comparisons with apses elsewhere is less substantial and therefore not entirely satisfying to a knowledgeable reader. For instance, he admits that similar inscriptions appeared outside of Rome in the fifth-century churches of Paulinus at Nola, while the sixth-century churches of the Basilica Eufrasiana at Poreč and San Vitale and Sant’Apollinare Nuovo at Ravenna include in their decoration clerical donor portraits and similar visual “litanies” of saints, titular or otherwise. Unfortunately, these examples beg the question of an exclusively Roman genesis or specific papal agenda within the development of apse compositions conforming to Thunø’s criteria and analysis.

In chapter 2, Thunø begins to explore the apse programs in their entirety, focusing on the presence of key iconographic features and interpreting the physical and pictorial structure primarily in terms of textual source material. The simultaneous and anachronistic elements of the apses mentioned in the first chapter are revealed to be only part of a great variety of heavenly and earthly visual elements that further underscore Thunø’s “synchronic” interpretation of the programs. The apse imagery encompasses the nature and scope of the universal Church while visual ambiguities collapse time and space into an eternal present. Though much of this analysis is synthetic, building on the more focused studies of other scholars and his own, Thunø is the first to compile and explain the breadth of these features in a systematic way.

Thunø argues that the chief function of apse imagery is to enable the community of worshippers to comprehend their place within the universal Church. He points out that post-apostolic saints take on a crucial role as mediators between viewer and viewed, between the earthly and the heavenly realms. By virtue of their shared humanity and frontal gaze, the saints connect with the audience who then become an integral part of the all-encompassing spiritual hierarchy revealed before their eyes. Thunø also sees the diversity of saints depicted and their varying social status as a means of directly relating to the ecclesio-civic experience of a broad audience constituency. Though this interpretation cannot compare with the populism of late medieval devotional practices, it is undeniable that the specificity and relative contemporaneity of the saintly figures enhance their accessibility. Surely, their appearance goes well beyond the twinning of SS. Peter and Paul in concordia apostolorum—a more generic means of referring to the early Church (ecclesia romana) as a communion of Jews and Gentiles.

Thunø reiterates existing scholarly opinion that peculiarities in the iconography of the apse arch decoration, which is derived from the Book of Revelation, deemphasize the eschatological focus of the source material. Instead, the images promote the concept of a celestial Church in perpetual celebration of the Godhead whose divinity is often indicated visually by clipeus or mandorla surrounds on the apex of the arch. The distance of the apse arch from the viewer and the understanding of the form of the arch as arc of the firmament make clear the physical and spiritual boundary between viewer and image. The apse vault, by contrast, is a more ambiguous space. Thunø interprets its decoration as an imagined theophany—distinct from biblical versions common in earlier apse decoration—in which the figure of Christ acts as a fulcrum around which the entire iconographic scheme unfolds. Thunø emphasizes biblical and exegetical sources that envision Christ as the Pauline metaphoric “cornerstone of the spiritual temple”; his presence is both foundation and support for the heavenly and earthly Church. The simultaneity of his human and divine nature is indicated by the juxtaposition of his full-figure, entirely human presence in the apse vault positioned along a vertical axis that connects him to his divine manifestation on the apse arch. A potential aspect that Thunø does not explore is how this visual message underscores Orthodox belief (i.e., “papal position”) of the nature of Christ—a theological theme of great historical import in the early medieval period and one that would demand visual consistency (i.e., “repetition”) in its own right. The ambiguity of Christ’s impending arrival or departure amid clouds is rightly linked by Thunø to the related themes of the Incarnation and Resurrection, the concurrence of which is a further implication of the suspension of time in these apse compositions.

In chapter 3, Thunø states that “there never was a strong and continuous tradition among the apse mosaics of Rome to explicitly evoke the liturgy of the Eucharist” (128). Iconographic connections between apse decoration and the Canon of the Mass are discussed primarily in terms of Carolingian pictorial evidence and their correspondences with apse arch imagery. Yet, the liturgy of the Eucharist is only part of a much more varied series of ritual actions that constitute the Mass. Surely groups of figures in attitudes of prayer and the hieratic arrangement of figures in, albeit static, procession are quite obvious references to the broader kinetics of liturgical performance within the physical church. Thunø’s statement that the apse is “the distinct zone in the space of the church through which the worshipper may gain access to heaven” (89) is made fully manifest by the intimate participation of worshippers in accepting and partaking of Christ in communion. Thunø stresses the role of Christ’s “oracular embrace” and the presence of human and saintly intermediaries as the means by which the congregation is united in the communio sanctorum. Membership among the “living stones” of the Church is envisioned most succinctly in the image of the Heavenly Jerusalem on the apse arch at S. Prassede.

Chapter 4 delves into the historical aspects of the cult of saints in Rome and the role of the papacy in its promotion. Thunø’s analysis of Pope Damasus’s cemeterial epigrams, which embraced topographically diffuse martyr saints and their relics within the devotional life of the Roman Church, shows them to be an early, somewhat non-specific forerunner of the early medieval papal agenda. Indeed, Thunø believes that Damasus’s reference to martyrs as “new stars” is implied in the spiritual “light” of the saints mentioned in various later apse inscriptions and made manifest in the splendid materials used in the mosaics. The medieval introduction and transfer of the remains of foreign and local saints respectively to sanctify altars was a way in which the popes could “maximize clerical control” (59) of relics, thereby—and unlike the Damasian program—underscoring daily the immediacy of papal and saintly mediation in the greater scheme of salvation.

The target of this papal program was more diverse, and likely more influential, than Thunø suggests. As he points out, the apses considered are located in churches that had a wide variety of functions. The aspects that do link them are the distinction of papal patronage and renewal, the incorporation of relics in the altars, and the appearance of these churches in pilgrimage itineraries of the period. Pilgrimage, as well as foreign immigration to Rome at the time, would motivate the popes to expand Thunø’s communio sanctorum in targeting the city’s fluid demographics. A more thorough discussion of this idea, as well as that of the growth of papal power and independence within the social, political, and theological upheaval of this period, would benefit his overall interpretation.

Despite Thunø’s purposeful eschewal of much historical context, he cannot deny the position of the apse of SS. Cosmas and Damian as the terminus post quem for his control group. Unfortunately, he does not explain its peculiar status as a work specifically relevant to the brief papacy of Felix IV, only the ability of its visual program to resonate over his selected time period. What Thunø is able to suggest with a degree of confidence is that all of the apse mosaics in question, and despite their iconographic differences, are able to tap into and replicate the particular ecclesiological ethos that first appears in the Forum church. And while they may have existed, extramural cemeterial pictorial models need not be imagined when the format of early Christian apses—replete with centralized figures of Christ flanked by saints in atemporal settings—are perfectly plausible antecedents. They certainly generated at least some ecclesiological content shared by their early medieval successors, and only the exigencies of survival diminish our ability to trace a more convincing connection and evolution. To be sure, a visual program of the themes of time, network, and repetition would also satisfy the doctrine of Petrine succession spanning the early Christian through medieval periods.