In early 2010 he wrote to a former student saying that any work published in his absence was done without permission, it should not be copied, and libraries possessing it should destroy it. Is this a cry for purity in a messy world, influenced by his early life as an adoptee, and subsequently a stateless refugee?

Euclid was certainly known in the ancient world as the author of the Elements, but did he perhaps abandon the gilded cage of that great library at Alexandria, leaving no trace except for his mathematics? We know that Apollonius of Perga (c.262-190 BC) refers to Euclid's work, and that Pappus of Alexandria (active in the 4th century AD) claimed Apollonius had studied under Euclid's pupils in Alexandria. But that's about all.

It may seem odd that anyone who achieves greatness can simply retire to solitude, but mathematicians inhabit an abstruse world, and can leave almost as abruptly as they enter. I'll leave the last words to the great Isaac Newton, who discovered the universal force of gravity, invented calculus, and explained Kepler's observations about planetary orbits thus:

"I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."

What Euclid thought of his own work we have no idea, but at a distance of more than 2,000 years the jury is unanimous: Elements is the greatest textbook of all time.