Dr Cat Jarman is a bioarchaeologist, specialising in forensic techniques to research the paths of Vikings who came to rest in British soil. By examining teeth that are now over one thousand years old, she can determine childhood diet, and thereby where a person was likely born. With radiocarbon dating, she can ascertain a death date down to the range of a few years. And her research offers new visions of the likely roles of women and children in Viking culture. In 2017, a carnelian bead came into her temporary possession. River Kings sees her trace its path back to eighth-century Baghdad and India, discovering along the way that the Vikings’ route was far more varied than we might think, that with them came people from the Middle East, not just Scandinavia, and that the reason for this unexpected integration between the Eastern and Western worlds may well have been a slave trade running through the Silk Road, and all the way to Britain. Told as a riveting story of the Vikings and the methods we use to understand them, this is a major reassessment of the fierce, often-mythologised voyagers of the north, and of the global medieval world as we know it.