From Iceland to Ethiopia, medieval Christendom produced an alarming number of saints. The vast majority of them commanded local or unofficial cults and never passed through the refining fires of papal canonisation. Popes canonised only 78 saints during the Middle Ages, beginning with St Ulric of Augsburg in AD 993. Yet, as Robert Bartlett calculates in this magnificent survey, across the Middle Ages there were perhaps 15,000 saints all told, roughly ten per year since the birth of Christ. To their critics, such as the distinctly Protestant devils of Cardinal Newman’s Dream of Gerontius, they remain a ‘bundle of bones, which fools adore’. By those seeking comfort or protection from an unpredictable world, the saints were not so easily dismissed. Their variety, their ability to bridge the gap between earth and eternity, their value as totems of identity or guides to moral behaviour, and in the end their sheer entertainment value, ensured them a central role in medieval society. Where modern escapists turn to biography, fantasy fiction or celebrity gossip, the Middle Ages looked instead to such bestsellers as Jacobus de Voragine’s Golden Legend, a vast compendium of the true, the wished for and the entirely imagined.