According to Anglo-Saxon chronicles, in the year 793 the Vikings arrived in Britain from Sweden, Denmark and Norway and savagely attacked the monks at Lindisfarne. Occasional plundering followed and later, in the 9th century, the Great Viking Army began to roam the island with a larger ambition: conquest. Between 865 and 873 they conquered Repton, where they overwintered, and occupied the Anglo-Saxon kingdom of Mercia. The official account is the one written by the Anglo-Saxons, but the sites may open up new perspectives. Archaeologist and bioarchaeologist Cat Jarman has spent more than six years analysing a mass grave at Repton, where 264 people are buried, many of them victims of the Great Viking Army's campaign. A semi-precious stone from Gujarat, India, was found in the Derbyshire village, leading Jarman to question the official account. How had it travelled from Asia to Repton in the 9th century? Jarman traces not only the stone, but also the skeletal remains. Who were the four children who were killed and who came from neither northern Europe nor England? And why are there many victims at Repton who were neither of Scandinavian nor Anglo-Saxon origin? In her book, River Kings, now translated into Spanish as Los reyes del río (Ático de los Libros), the Vikings are still hardened warriors, but Jarman shows them to be much more enterprising and pragmatic than they usually are on TV.