[28] According to the sketch of his life in Buhle (Arat. Opp. i. 3), Aratus was a pupil of Persæus at Athens, in company with whom he repaired to Antigonus in Macedonia, which can only mean that he was, together with Persæus, a pupil of Zeno. Another writer in Buhle (ii. 445) calls him so, mentioning one of his letters addressed to Zeno. Other accounts (Ibid. ii. 431; 442; 446) describe him as a pupil of Dionysius of Heraclea, or of Timon and Menedemus. A memorial of his Stoicism is the introduction to his ‘Phænomena,’ a poem resembling the hymn of Cleanthes. Asclepiades (Vita in Buhle, ii. 429), in calling him a native of Tarsus, is only preferring a better-known Cilician town to one less known. [29] Hence his name ὁ Μεταθέμενος. On his writings, consult Diog. vii. 166; 37; 23; v. 92; Athen. vii. 281, d; x. 437, e; Cic. Acad. ii. 22, 71; Tusc. ii. 25, 60; Fin. v. 31, 94. Previously to Zeno, he is said to have studied under Heraclides ὁ Ποντικὸς, Alexinus, and Menedemus. [30] Diog. 177; Plut. Cleomen. 2; 11; Athen. viii. 354, e. Sphærus’ presence in Egypt seems to belong to the time before he became connected with Cleomenes. He was a pupil of Cleanthes (Diog. vii. 185; Athen. l.c.) when he went to Egypt, and resided there at the court of Ptolemy for several years. He had left Egypt by 221 B.C., but was then himself no longer a member of the Stoic School at Athens. It is possible that Sphærus may first have come to Cleomenes on a commission from the Egyptian king. In that case, the Ptolemy referred to must have been either Ptolemy Euergetes or Ptolemy Philadelphus—certainly not Philopator, as Diog. 177 says. If, however, the view is taken that it was Ptolemy Philopator, it may be supposed that Sphærus repaired to Egypt with Cleomenes in 221 B.C. Sphærus’ numerous writings (Diog. 178: Λακωνικὴ πολιτεία also in Athen. iv. 141, 6) refer to all parts of philosophy, and to some of the older philosophers. According to Cic. Tusc. iv. 24, 53, his definitions were in great esteem in the Stoic School. [31] Athenodorus, a native of Soli (Diog. vii. 38; 100); Callippus of Corinth (Diog. 38); Philonides of Thebes, who went with Persæus to Antigonus (Diog. 9; 38); Posidonius of Alexandria (Diog. 38); Zeno of Sidon, a pupil of Diodorus Cronus, who joined Zeno (Diog. 38; 16; Suid.). [32] Baguet, De Chrysippo. Annal. Lovan. vol. iv. Lovan. 1822. [33] Εἰ μὴ γὰρ ἦν Χρύσιππος οὐκ ἂν ἦν στοά (Diog. 183). Cic. Acad. ii. 24, 75: Chrysippum, qui fulcire putatur porticum Stoicorum, Athen. viii. 335, b.: Χρύσιππον τὸν τῆς στοᾶς ἡγεμόνα. See Baguet, p. 16.