Not much younger than these (sc. Hermotimus of Colophon and Philippus of Mende) is Euclid, who put together the Elements, collecting many of Eudoxus' theorems, perfecting many of Theaetetus', and also bringing to irrefragable demonstration the things which were only somewhat loosely proved by his predecessors. This man lived in the time of the first Ptolemy. For Archimedes, who came immediately after the first (Ptolemy), makes mention of Euclid: and, further, they say that Ptolemy once asked him if there was in geometry any shorter way than that of the elements, and he answered that there was no royal road to geometry. He is then younger than pupils of Plato but older than Eratosthenes and Archimedes; for the latter were contemporary with one another, as Eratosthenes somewhere says.
5th-century Greek Neoplatonist philosopher
Lycaeus (8 February 412 – 17 April 485 AD), called the Successor, was a Greek Neoplatonist philosopher. As one of the last major classical philosophers, he set forth an elaborate and fully developed system of Neoplatonism, which had a profound influence upon Western medieval philosophy. His commentary on the first book of Euclid's Elements is one of the most valuable sources we have for the history of ancient mathematics, and its Platonic account of the status of mathematical objects was also influential.
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It is told that those who first brought out the irrationals from concealment into the open perished in shipwreck, to a man. For the unutterable and the formless must needs be concealed. And those who uncovered and touched this image of life were instantaneously destroyed and shall remain forever exposed to the play of the eternal waves.