On the astrolabe presented by the young German astronomer Regiomontanus to his ageing patron Cardinal Bessarion there is a Latin epigram and the image of an angel. The former is a geometrically-arranged acrostic with eight hidden vertical axes. Of these, the two principal ones correspond precisely to the two principal axes of the enigmatic painting The Flagellation of Christ by Piero della Francesca. In this are five figures in a flagellation scene on the left and three modern figures on the right, including a bearded Greek and an angelic young man in cardinal red.

Over 40 interpretations of the three moderns have been proposed over the past 150 years.

In this book, David King shows how clusters of letters across the epigram reveal double or multiple identities for each and every one of the eight persons in the painting. The only new person in the drama is Regiomontanus, whose epigram provided the inspiration for the painting. His image embodies three talented young men close to Bessarion who had recently died, and also symbolizes the cardinals hope for the future.