The Hammer and the Cross: A New History of the Vikings, By Robert Ferguson

One of the strengths of this "new" historical account of the Vikings is that Robert Ferguson stresses the extraordinary sweep of the invaders. Many will be familiar enough with Viking raids on York and Iona and with the viciousness of Hengest and Horsa, and the English language is full of Norse words. But the Viking influence stretched all the way to the Balkans and beyond, to Byzantium, thanks to their aggressive trading practices. They challenged Charlemagne's massive kingdom with raids of more than 100 ships at a time. They were an even more fearsome force than we have always believed them to be.

One of the weaknesses of Ferguson's overview is that it is an overview, and a sense of who the Vikings were as people gets lost. It's hard to know what motivated them, apart from rape and pillage – though Ferguson follows other historians in arguing that poverty and the lack of food forced the Vikings to travel, and that the pillaging of churches was a political act by heathens against Christians.

This dearth of personal detail is partly a consequence of the Vikings being an illiterate people: the first documentation comes 300 years later. But discoveries of ship burials do hint at possible personal histories: a woman buried with herbs associated with witchcraft; a young girl with damaged bones.

Ferguson retells the histories of great warriors such as Harald Bluetooth and Erik the Red, and provides faultless accounts of battles with the Saxon and English kings Alfred and Edward, emphasising the Vikings' capacity for violence and grisly executions. But one of the few women to make an appearance, the fascinating figure of Ethelfled, widow of Ethelred, who campaigned and organised forces, is only tantalisingly glimpsed. And a sense of them as individuals? I struggled to feel it.