‘The moon wanes and waxes, it is never steadfast’, wrote the author of Ancrene Wisse, a 13th-century guide for English anchoresses, ‘and signifies therefore worldly things that are as the moon ever changing.’ For anchorites immured in their cells, the moon represented everything they had rejected, the material pleasures and temptations they had overcome. But, as Ayoush Lazikani amply demonstrates in The Medieval Moon, the only things less steadfast than the moon itself for the people of the Middle Ages were the meanings they drew from it.

Even within Christian thought, its meanings were varied and contradictory. For Bernard of Clairvaux, a leading figure in the Cistercian order, the moon was a metaphor for the Church itself: just as the light of the moon was reflected from the sun, so the Church was a reflection of the light of God. Pope Innocent III used the same understanding of cosmology to make a different point: for him, the pope was the sun while the Holy Roman Emperor was the moon, his authority a mere reflection of papal power and glory. For the Sufi mystic Ibn Arabi, meanwhile, the moon was the divine itself. ‘You are majestic, a full moon risen within me, a moon that never sets,’ he wrote.

Lazikani devotes a chapter each to six aspects of lunar thinking: riddles and mysteries; travel and adventure; prophecies and signs; illnesses and cures; sorrows and illusions; love and embraces. As is perhaps apt, the categories hint at but do not wholly reveal the depth of medieval thinking about the moon