By Simon Davies, Painted Hall Ceiling Tour guide

21 May 2018

The letter A in the title could equally stand for armillary sphere or Archimedes as they both provide significant clues to the identity of the bald headed and bearded man standing appropriately between the two. Tucked away at the west end of Painted Hall ceiling, I believe that the man represented here is the Greek mathematician, astronomer, geographer, poet and all-round multitasker Eratosthenes (c. 276 – 194 BC).

From left to right: Urania, muse of astronomy, holds a golden armillary sphere, just to her right is the bearded man who I suggest is Eratosthenes, looking down towards the red-cloaked figure of Archimedes.

The armillary sphere (a model illustrating the movement of the heavens) is held aloft by the star-haloed figure of Urania, the muse of astronomy. According to the Greek astronomer Hipparchus, Eratosthenes invented the armillary sphere. Archimedes, one of the greatest mathematicians of all time, is pictured to the right of Eratosthenes, staring intently upwards and seemingly engaged in conversation with the person who was his friend and contemporary. The identification is supported by similarities between James Thornhill’s depiction of the bearded man and engravings of Eratosthenes.

Left: Eratosthenes looking down towards Archimedes

Right: Engraving of Eratosthenes

Born in the town of Cyrene, in modern day Libya, Eratosthenes acquired the nickname Beta (the second letter of the Greek alphabet) for reputedly being second best at everything; however his many accomplishments would suggest otherwise. Following an education in Athens, he became the third chief custodian of the Library at Alexandria, one of the great centres of learning in the ancient world. He coined the word ‘geography’ in relation to the study of the earth, became the first person to produce a remarkably accurate calculation of the earth’s circumference and created a simple algorithm for finding prime numbers, known as the ‘sieve of Eratosthenes’.

 Perhaps though it was his association with a text called Catasterismi that earned him a place on Thornhill’s ceiling. The ancient Greek term ‘Catasterism’ is defined as a ‘placing amongst the stars’ and became the working title for a compendium or encyclopedia of stories that describe the mythological origins of the constellations; stories supposedly gathered and contributed to by Eratosthenes. It is little coincidence then that Urania, with rod in hand, directs our attention to the constellations portrayed on the celestial globe; essential astronomical signposts for early mariners to steer and navigate by.

Detail of Urania’s celestial globe

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