Al-Khalili ably demonstrates the depth of scientific knowledge within the Islamic world at a time when European engagement with science was rather feeble, except in Muslim Spain.

Her emphasis on the role of Arab science – or perhaps one should say Middle Eastern science, since Persian, Jewish and other non-Arab writers played a significant role too – mirrors the approach of popularisers such as Jim Al-Khalili in his book Pathfinders. In the fashion of such works as Jerry Brotton’s A History of the World in Twelve Maps and Tristram Hunt’s Ten Cities That Made an Empire, she builds her narrative around a small number of documents and places with the aim of illustrating the way in which key classical texts were transmitted from antiquity through the Islamic world and on to medieval and Renaissance Europe. Moller attempts to emulate Adelard’s haute vulgarisation. The Arabic translators had interspersed their texts with explanations of terms and concepts the meanings of which in the original Greek puzzled western European readers, even if (as was rarely the case) they could understand that language. Nor was he alone in taking such a route: works such as Ptolemy’s Almagest, fundamental for the medieval study of the heavens, seemed to inhabitants of Christian western Europe easier to understand through translation of the Arabic version rather than of the Greek original. Adelard knew that court well, but what is particularly interesting is that when he translated Euclid’s Elements into Latin he chose to do it not from its original Greek, the language of nearly half the population of Sicily at that time, but from Arabic, the language of the other half. Yet he also devoted a good part of his time to profound research, translating mathematical, astronomical and astrological texts from Arabic – astrology being regarded in his time, especially at the Norman court in Sicily, as a very exact science with medical as well as political uses. This 12th-century English scholar, arrayed in his striped hat, brilliant green or red cape and lapis lazuli shirt, ‘had a talent’, Violet Moller explains, ‘for communicating complex scientific ideas and adapting them for an amateur, but interested, audience’. Adelard of Bath would be in demand in the present day.

The map of knowledge by violet moller