In hindsight, the religious, artistic and scientific endeavours of any given period are dominated by a number of pre-eminent works and by a few commanding names, designated ‘the greatest geniuses’ by eighteenth-century writers. Leading figures have taken knowledge forward, but never claimed that their abilities surpassed those of their great predecessors. The twelfth-century theologian Bernard of Chartres, as reported by John of Salisbury, had a memorable phrase:

Bernard of Chartres used to compare us to dwarfs perched on the shoulders of giants. He pointed out that we see more and farther than our predecessors, not because we have keener vision or greater height, but because we are lifted up and borne aloft on their gigantic stature.

These words were echoed in the seventeenth century by Isaac Newton, the greatest scientist of his day.

A lasting authority has been bestowed on certain works, and this is eloquently expressed in copies that have been made of them. A fine ninth-century manuscript of Euclid’s Elements, copiously annotated by its first owner, was a part of a movement then flourishing in Byzantium in which the most highly regarded texts of classical Greece were copied and preserved. A beautiful manuscript of the Rule of St Benedict was made with devotion in early eighth-century England, when the Benedictine order was still fully to establish itself in that country. A translation of Gregory I’s Pastoral Care was commissioned by Alfred the Great at the end of the ninth century as part of his revival of English learning after years of war.

Important scientific developments have taken authoritative texts for their starting-point. Ptolemy’s great mapping of the earth and the heavens served as the models for astronomical and geographical work for centuries, and formed the basis of works by tenth-century Islamic court astronomer al-Ṣūfī and the twelfth-century Arab geographer al-Idrīsī. Ptolemy’s Geography dictated the form of the first atlases printed in the West, even after the discoveries of the great fifteenth-century explorers. The work of the classical Greek physician Dioscorides was absorbed by Islamic scholars and inspired one of the most ambitious publishing ventures of the nineteenth century, John Sibthorpe’s Flora Graeca.