That the Dark Ages were not so dark as the historians of the Enlightenment and the nineteenth century believed is now a truism. As a result, the subtitle of Nancy Marie Brown’s biography of Gerbert, the tenth-century Archbishop of Reims who became a close adviser of the Holy Roman Emperor Otto III, and then pope, taking the name Sylvester II, seems dubious. For years historians have been writing of the ‘Carolingian Renaissance’ of the eighth and ninth centuries, and it has long been recognised that there was a cultural and intellectual exchange between Muslim Spain and France, Germany, Italy, and even England.

The materials available to Brown are considerable, yet too meagre for a full biography. She tells us that Gerbert ‘left us over two hundred letters and a handful of scientific treatises’, and adds that ‘he is mentioned in the letters or chronicles of several men who lived during