To the extent that history is about people, as well as being the politics of the past, political biography remains an essential way of reading and writing it. This is especially true for ancient and medieval societies, where autocratic rulers adopted high political profiles and the surviving written record is largely structured around their personal reigns. Yet the profiling of rulers in ancient and medieval sources presents the modern historian with a particular challenge, since it is all too often deficient in objective, coherent, incisive and contextualised explanations for political actions and decisions. Faced with the inadequacy of biographical information, scholarship since the nineteenth century on Roman and Byzantine emperors has opted for one, or a combination, of three approaches. One is to write a history of ‘the age of X’, in which the biographical narrative is subordinated to descriptive analysis of the geopolitical, social, economic and cultural context. Another is to foreground a biographical narrative that relies on a critical but positivist ranking and harmonisation of the sources, combined with intuitive conjecture to fill in the gaps of the evidence. Both these approaches are driven by the issues rather than the evidence. The third approach prioritises the evidence, or rather, it treats the evidence as the principal point at issue, and aims to provide the prolegomena for a biographical narrative, by subjecting the sources to exhaustive philological and narratological deconstruction.

Juan Signes’ 500-page study of an emperor who ruled for thirteen years and died around the age of forty combines the second and third approaches. It answers the need for a biographical, narrative focus on a controversial, high-profile ruler who gave rise to an extraordinary number of anecdotes. Its overriding concern is to establish a correct chronological sequence for the crowded events of Theophilos’ career. At the same time, it subjects the evidence for each event to an exhaustive, analytical review, so that the book reads more like a series of critical essays than a narrative synthesis. Although this does not make life easy for the reader, it is entirely justifiable, given the previous scholarship on Theophilos. In the state of this scholarship, the most pressing need was for a study to unpick the synthesis put forward by John Rosser in his 1972 PhD thesis, and refined and popularised by Warren Treadgold in his book The Byzantine Revival, 780–842 (1988), which featured Theophilos as the culminating, tragic hero. Treadgold was well aware of the opaque and tangled complexity of the sources for Theophilos, but he chose not to let it spoil the flow of his narrative, and only indicated in his endnotes the degree of conjectural interpretation on which his confident statements were based. Problems of Quellenkritik, by contrast, come to the fore in every chapter of the book here reviewed. The Greek sources nearly all reflect the ideological reaction against the religious policy of the last iconoclast emperor, and most postdate the overthrow of his dynasty by Basil I the Macedonian. The main Greek historical narratives were put together over a hundred years after Theophilos’ death, so the authors of these texts were working with excerpts and paraphrases from earlier sources, whose relationship they were liable to misjudge when trying to make sense of them. The Arabic histories were similarly open to distortion at the hands of tenth-century editors. The chronicler who most faithfully reproduces the information of his ninth-century sources is, paradoxically, the thirteenth-century Michael the Syrian.

The author was clearly inspired, and highly qualified, to write this book by his deep familiarity with Greek literature of the ninth and tenth centuries, and especially with the most important narrative text, the Continuation of Theophanes’ Chronicle, to which he devoted a ground-breaking monograph in 1995, and of which he is completing, with Michael Featherstone, the critical edition begun long ago by the late Ihor Ševčenko. It is somewhat regrettable, therefore, that he has not dedicated a chapter to a detailed discussion of the sources, and in particular of the now-lost narratives that lie behind the accounts of Theophanes Continuatus and the other tenth-century historians (Genesios and the various recensions of the Logothete Chronicle). It would be pertinent to this study to consider the literary origin of the many biographical anecdotes that circulated about Theophilos and his associates. Perhaps Signes considers that he has already dealt adequately with this subject in his monograph – but that was twenty years ago, and in Spanish.

There are other omissions – notably iconoclasm within the empire, and the West – that would be regrettable in a work that set out to be a comprehensive monograph on Theophilos. However, the author states that this was not his intention. As it is, he has produced a larger than average book that fully justifies its concentration on the eastern sector of Byzantine imperial interests in a period that saw the last peak of Abbasid aggression under the sons of Harun al-Rashid, the caliphs Ma’mūn and Mu’taşim. In pursuing the exact chronology of events on and around the Byzantine frontier with the Caliphate from 819 to 842, Juan Signes is led to revise several assumptions, which appeared to be set in stone, about the politics, strategy and prosopography of the empire's eastern command. Thus he postulates the existence of a strong Armenian aristocratic lobby at the Byzantine court in Theophilos’ early years, which partly reflected the emperor's attempt to reconnect with the regime of his godfather, Leo V, whom his father, Michael II, had overthrown. He distinguishes between Thomas the Armenian and Thomas the Slav, and argues that the latter's attack on the regimes of Leo V and Michael II was not fundamentally a Byzantine civil war but an Abbasid invasion, in which Thomas owed both his initial success and his ultimate failure to the fact that he was a puppet of the caliph Ma’mūn. Ma’mūn used him in the way that the Byzantines used the disaffection of the Caliph's Persian Khurramite subjects. In clarifying the nature of the Khurramite movement and its Byzantine connection, Signes makes a bold, but eminently sensible, reinterpretation of the evidence concerning the noble Persian exiles in Theophilos’ entourage: ‘Theophobos’ was not simply the baptismal name of the person referred to as Naşr, but a different individual, most likely the other's son, whom Naşr had left to be brought up at the court of Constantinople during his visit under Michael II.

Signes further suggests that other Byzantine setbacks of the 820s, the Aghlabid invasion of Sicily and the seizure of Crete by a company of Andalusian exiles, were not coincidental, but coordinated by Ma’mūn. Seen in this light, Theophilos’ strategy of retaliation does not seem unimpressive. The central section of the book is devoted to the painstaking task of distinguishing, dating and evaluating the campaigns that the emperor and the caliphs launched against each other during the 830s. The arguments are often complex and the conclusions tentative, but on balance they support the idea that the Byzantine war effort under Theophilos was more sustained and effective than has generally been supposed. Above all, a careful reading of the non-Greek sources suggests that the war effort did not collapse, and Theophilos did not give up in despair, after the caliph's capture and sack of Amorion in 838, the emperor's birthplace and the empire's main centre of operations in Asia Minor; indeed, Mu’taşim was fortunate to be able to extricate himself and his army from his overextended offensive. Theophilos supported his war-effort in Asia Minor with continuously pro-active diplomacy on other fronts: he cultivated an alliance with the Umayyad emirate of Cordoba against their common Abbasid enemy, and a revised dating of his intervention in support of the Khazars against the Magyars leads to the conclusion that he transferred his recognition from the Khazar khagan to the newly emergent power of Rus as the empire's main partner in the lands to the north of the Black Sea.

Signes sees evidence for the effectiveness of Theophilos’ eastern policy in the reaction it elicited from the Melkite (‘Greek Orthodox’) Christians under Muslim rule. Perhaps the most interesting and impressive piece of Quellenkritik in the volume is the reinterpretation of the ‘Letter of the three patriarchs’. In its surviving form, this document purports to be a letter from the patriarchs of Jerusalem, Alexandria and Antioch to the emperor Theophilos making the case for the veneration of icons. The critical edition of this text in 1997 made clear what was already quite obvious: that it was a piece of iconophile propaganda produced after the death of the last iconoclast emperor. However, uncertainty remained as to whether it was a complete forgery, or the result of heavy interpolation. Following the editors of 1997, Signes demonstrates that the sections of the text most likely to be authentic are precisely those that speak of holy imagery in the notional sense favoured by the iconoclasts. Two important conclusions emerge from his analysis. Firstly, the Melkite churches in the eighth and ninth centuries were by no means as committed to icon veneration as the careers of some prominent individuals, such as John of Damascus and Michael the Synkellos, have suggested. Secondly, in the 830s their leaders nurtured hopes for an end to Muslim rule, encouraged by the energetic campaigning of Theophilos, as well as by current prophecies, both Christian and Islamic, that predicted the end of the Abbasid hegemony.

No study of Theophilos and the East would be complete without some discussion of the cultural relations and intellectual exchanges between Constantinople and Baghdad in the early ninth century. The concluding chapter of the book provides a useful summary of the state of research, though if new insights are to be gained, they will come from the younger scholars who are working in this area.

The epilogue, in addition to recapitulating the results of the preceding chapters, deals with the other distinctive aspects of Theophilos’ image and legacy: his populism and his reputation for justice, reflected in many of the anecdotes about him. It would be unfair to complain that the book, which is does not claim to be comprehensive and is already quite long, does not take this discussion further. However, it is interesting and important to consider why these stories about Theophilos were retold in the literature of the late ninth and tenth centuries: what does this say about contemporary perceptions of the Macedonian dynasty, and what are its implications for understanding the policy ideals pursued and propagated by the Macedonian emperors? The same goes for other aspects of Theophilos’ regime that are documented in the sources of the Macedonian period, and were echoed in the policies of the first Macedonian emperor; one thinks notably of this emperor's palace buildings, and his extensive Armenian connection. These are important questions for the definitive study of Theophilos that Juan Signes will hopefully go on to provide and that he has certainly inspired, not least by raising the stakes of the verdict that Theophilos was ‘the unlucky’.

One can only be grateful that Juan Signes, who has published extensively in Spanish, decided to exert his formidable linguistic skills and make this work available in English. Some minor quirks – e.g. ‘provisory’ for ‘provisional’, ‘confound’ for ‘confuse’, and some unusual usage of prepositions – subsist as reminders that English is not the author's native language, but they evidently did not bother the native speaker who read the manuscript prior to publication, and they certainly do not get in the way of reading and appreciating this major contribution to scholarship.