In hindsight, the religious, artistic, and scientific endeavors 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.

A lasting authority has been bestowed on certain works, and this is eloquently expressed in copies that have been made of them. Important scientific developments have taken authoritative texts for their starting-point. The twelfth-century theologian Bernard of Chartres, as reported by John of Salisbury, ‘used to say that we are like dwarfs perched on the shoulders of giants, and thus we are able to see more and farther than the latter.’ These words were echoed in the seventeenth century by Isaac Newton, the greatest scientist of his day.