Suidas, s.v. Ἐρατοσθένης
Ἐρατοσθένης, Ἀγλαοῦ, οἱ δὲ Ἀμβροσίου· Κυρηναῖος, μαθητὴς φιλοσόφου Ἀρίστωνος Χίου, γραμματικοῦ δὲ Λυσανίου τοῦ Κυρηναίου καὶ Καλλιμάχου τοῦ ποιητοῦ. μετεπέμφθη δὲ ἐξ Ἀθηνῶν ὑπὸ τοῦ τρίτου Πτολεμαίου καὶ διέτριψε μέχρι τοῦ πέμπτου. διὰ δὲ τὸ δευτερεύειν ἐν παντὶ εἴδει παιδείας τοῖς ἄκροις ἐγγίσαντα1 Βῆτα2 ἐπεκλήθη. οἱ δὲ καὶ δεύτερον ἢ νέον Πλάτωνα, ἄλλοι Πένταθλον ἐκάλεσαν. ἐτέχθη δὲ ρκϛʹ Ὀλυμπιάδι
Suidas, s.v. Eratosthenes
Eratosthenes, son of Aglaus, others say of Ambrosius; a Cyrenean, a pupil of the philosopher Ariston of Chios, of the grammarian Lysanias of Cyrene and of the poet Callimachusb; he was sent for from Athens by the third Ptolemyc and stayed till the fifth.d Owing to taking second place in all branches of learning, though approaching the highest excellence, he was called Beta. Others called him a Second or New Plato, and yet others Pentathlon. He was born in the 126th Olympiade and died at the age
- aSeveral of Eratosthenes’ achievements have already been described—his solution of the Delian problem (vol. i. pp. 290–297), and his sieve for finding successive odd numbers (vol. i. pp. 100–103). Archimedes, as we have seen, dedicated the Method to him, and the Cattle Problem, as we have also seen, is said to have been sent through him to the Alexandrian mathematicians. It is generally supposed that Ptolemy credits him with having calculated the distance between the tropics (or twice the obliquity of the ecliptic) at 11/83rds. of a complete circle or 4° 42΄ 39″, but Ptolemy’s meaning is not clear. Eratosthenes also calculated the distances of the sun and moon from the earth and the size of the sun. Fragments of an astronomical poem which he wrote under the title Hermes have survived. He was the first person to attempt a scientific chronology from the siege of Troy in two separate works, and he wrote a geographical work in three books. His writings are critically discussed in Bernhardy’s Eratosthenica (Berlin, 1822).
- bCallimachus, the famous poet and grammarian, was also a Cyrenean. He opened a school in the suburbs of Alexandria and was appointed by Ptolemy Philadelphus chief librarian of the Alexandrian library, a post which he held till his death c. 240 b.c. Eratosthenes later held the same post.
- cEuergetes I (reigned 246–221 b.c.), who sent for him to be tutor to his son and successor Philopator (v. vol. i. pp. 256, 296).
- dEpiphanes (reigned 204–181 b.c.).
- e276–273 b.c.