Edward Gibbon, the 18th-century chronicler of the decline and fall of the Roman Empire, memorably described the Gothic ruler Alaric as ‘a victorious leader, who united the daring spirit of a barbarian with the art and discipline of a Roman general’. The Roman poet Claudian, a contemporary of Alaric, took a harsher view of the barbarian warlord’s behaviour: it was akin to ‘how/pirates act, terrors to the sea,/when they see their life of crime/finally runs aground’.

Alaric’s crime, in Claudian’s eyes, and those of many subsequent historians who took their cue from him, was the sack of Rome in 410, an act thought by some more excitable Christian authors of that period to herald the end times. Douglas Boin’s Alaric the Goth is a revisionist attempt to rescue Alaric’s reputation. He sets out, as the title suggests, to look at Alaric’s career from the outside and not from the decline-centred perspective of the imperial court. The challenge is considerable, not least because the evidence – as with many figures of classical antiquity – is so scarce: as the author admits, ‘the public record of Alaric’s life is frustratingly thin. Whole decades of his existence have simply vanished.’ While Gibbon summarised Alaric’s career in a few pages of crisp prose, Boin is forced to stretch his material more thinly, straying from his central character to paint a portrait of life on the frontier of the Roman Empire in the fourth century that is both evocative and instructive of Alaric’s formation, motivation and rise to fame.

Like many a subsequent empire, Rome had a highly ambivalent relationship with the outsiders it needed to fuel its commerce, stock its slave markets and man its armies. In this particular case, those outsiders were not colonised peoples but the Germanic barbarian tribes living in areas against which the waves of Roman imperialism had only lapped during the empire’s high tide, before it began to recede in the third century. The Danube basin, where Alaric grew up in the 370s, seems from Boin’s account an idyllic place: his family home bore the bucolic name Pine Tree Island and Boin conjures an image of infant Goths listening to tales of their heroic ancestor King Berig, who had led his people – perhaps understandably – out of a homeland of ‘quaking bogs’ called Scandza. Yet it was also a place of profound danger: of slave traders who kidnapped young girls in order to sell them south of the river, of ghosts and demons and, most threatening of all, of predatory Roman officials whose actions in trying to starve would-be migrants who were crossing the imperial frontier led to the first mass Gothic raids on the Balkans.

The Goths wanted to be Roman, or at least to live on Roman soil. The Romans, most especially the upper-class conservative policymakers from whom we hear the most, feared that romanitas, the essential core of what it meant to be Roman, was threatened with dilution by the influx of Germanic migrants, yet acknowledged that without their support the empire was incapable of defending itself. It is this tension that lies at the heart of Boin’s book and explains the fatal intertwining of Alaric’s career and the fall of Rome. Although the likes of Bishop Synesius could intone – in a hardly Christian manner – of Germanic migrants, ‘The shepherd must not mix wolves with his dogs, even if, caught as whelps, they may seem to be tamed’, such individuals were nevertheless admitted into some of the highest offices in the empire: think of Stilicho, the half-Vandal general who defended the weakling emperor Honorius from all comers until his petulant charge turned on him and had him murdered in the Ravenna marshes in 408, or of Gainas, another Goth, who rose to military command in the eastern part of the empire, only to be betrayed by Honorius’s brother Arcadius, murdered and memorialised in gruesome fashion on a marble column in Constantinople, which portrayed every last detail of his dismemberment.

Such episodes tell us much about the world into which Alaric was entering when he encountered the cavalcade of Emperor Theodosius in 391 and was enticed from a life of low-level banditry to become the Roman Empire’s latest barbarian recruit. Theodosius was a ruler who understood better than his co-emperors or successors the need to balance competing views of romanitas – he once massacred seven thousand citizens of Thessalonica to avenge the murder of its Gothic chief of police, Butheric – but the tensions bubbling up within the empire were too great. His hardline pro-Christian policies, which included the closing down of pagan temples and even, in 393, the prohibition of domestic offerings to the old gods, bewildered conservative senators in Rome, who in 394 raised up one of their own, Flavius Eugenius, in an attempt to usurp him. All of this aroused the suspicions of the Goths, who adhered to Arianism, a heterodox form of Christianity.

Boin ably describes these cross-currents through which Alaric bobbed, almost but not quite ever reaching the prize of acceptance at the imperial court. He rose to become magister militum in Illyria, the eastern empire’s chief military officer, only to be summarily sacked in 401, whereupon he returned to raiding. A complex series of political and military manoeuvres involving Stilicho, who started out as a foe but, from expediency, became an ally, finally led Alaric to invade the Italian peninsula, first in 401 and then, frustrated that his dreams of emulating so many of his barbarian peers and gaining imperial acceptance had never been realised, again in 408, when he camped at the gates of Rome.

The sack, which came two years later, was of a city that had long since ceased to be the arena of real power – this now lay in Ravenna, where Honorius skulked, and far-off Constantinople – but it had a profound symbolic effect, marking the end of the pretence that Rome was in control of its own destiny, able to play off the barbarians against each other, reward them when expedient and betray them when convenient. It is a story that Boin tells adeptly. Frustrated by the breakdown of negotiations with Honorius, who refused to accede to Alaric’s demand for land and a pay-off that included three thousand pounds of pepper, in the early summer of 410 Alaric and his host took up positions outside the walls of Rome. The fortifications were more than ample to keep him out, but at the dead of night, a supporter inside unlatched the small Salarian Gate and the Goths poured in, unleashing a three-day reign of terror on the Eternal City. Although the physical damage was slight – a few villas were burned on the Aventine and a handful of captives were murdered – the psychological damage was profound.

Boin offers valuable insights into a culture that, while in crisis, was still vibrant, and provides tantalising glimpses into a frontier world that is so often glossed over. Boin conjures the sense of bitter disappointment that coloured Alaric’s last months. Once his warriors had extracted what plunder they could, there was little sense in remaining in Rome, so he led his Gothic army south along the Via Appia, hoping to cross over into North Africa and establish a new Gothic homeland around Carthage, safe from imperial vengeance. Yet a storm prevented the evacuation and a few weeks later Alaric died of ‘a sickness’, knowing that all his hopes for his people – not to say his own career – had been unrealised. Even his burial site – the confluence of two rivers somewhere in southern Italy, deliberately chosen so that the waters would wash away all trace of it – is unknown, an oblivion from which Boin cannot fully rescue him.

The full details of Alaric’s life are now unrecoverable. What Boin gives us instead is a finely crafted account of how Alaric became the embodiment of Rome’s self-defeating fear of the world outside its frontiers.