SICYON (or SECYON, the older local form), an ancient Greek city in northern Peloponnesus between Corinth and Achaea, on a low triangular plateau about 2 m. from the Corinthian Gulf, at the confluence of the Asopus and the Helisson. Between city and port lay a fertile plain with olive-groves and orchards. Its primi tive name was Aegialeia "beach-town"; its original population Ionian; the myth and cult of Adrastus show early connection with Argos; and in the Iliad it is a dependency of Agamemnon. After the Dorian invasion it had the three Dorian tribes with an equally privileged tribe of Aigialeis (probably old Ionian) and a class of land-serfs (Koptninc/oOpot or Karawalcoclx5pot). For some centuries Sicyon remained subject to Argos, and acknowledged a certain suzerainty as late as 500 B.C. But virtual independence was estab lished in the 7th century by anti-Dorian tyrants, known after their founder as the Orthagoridae, whose mild rule lasted longer than any other Greek tyranny (about 665-565 B.c.). The founder's grandson Cleisthenes held intercourse with many commercial centres of Greece and south Italy and gave his heiress in marriage to Megacles of Athens, whose son was the Athenian legislator of that name. Cleisthenes (q.v.) besides reforming the city's consti tution and replacing Dorian cults by the worship of Dionysus, was chief instigator of the First Sacred War (59o) in the in terest of Delphi. After the fall of the tyranny, Cleisthenes' insti tutions survived till the end of the 6th century, when Dorian supremacy was re-established, and the city joined the Pelopon nesian League. Henceforth its policy was usually determined by Sparta or by its powerful neighbour Corinth. During the Persian wars Sicyon furnished 3,00o heavy-armed men; its school of bronze sculptors produced Canachus (q.v.) a master of the late archaic style. In the 5th century it suffered like Corinth from the commercial rivalry of Athens and was repeatedly harassed by Athenian ships. In the Peloponnesian war Sicyon followed Sparta and Corinth. Again in the Corinthian war Sicyon sided with Sparta. In 369 when it was captured and garrisoned by the
Thebans a powerful citizen Euphron established himself tyrant by popular support. His deposition by the Thebans and sub sequent murder freed Sicyon for a while, but new tyrants arose with the help of Philip II. of Macedon. Nevertheless during this period Sicyon reached its zenith as a centre of art : its school of painting under Eupompus attracted Pamphilus and Apelles as students ; its sculpture culminated in Lysippus and his pupils. After participating in the Lamian war and the campaigns of the Macedonian pretenders the city was captured (303) by Demetrius Poliorcetes, who transplanted the inhabitants to the Acropolis and renamed the site Demetrias. In the 3rd century it passed from tyrant to tyrant, until in 25I it was liberated and enrolled in the Achaean League (q.v.). The destruction of Corinth (146) brought an acquisition of territory and presidency over the Isthmian games ; yet in Cicero's time Sicyon had fallen deep into debt. Under the empire it was quite obscured by the restored Corinth and Patrae; Pausanias (A.D. 150) found it almost desolate. In Byzantine times it became a bishop's seat, and its later name "Hellas" reveals it as a refuge for Greeks from Slavonic immi grants of the 8th century.
An insignificant village, Vasiliko, now occupies the site. Ancient fortifications are still visible, and remains of a theatre, a stadium, aqueducts and foundations of buildings.
BIBLIOGRAPHY.—Strabo, pp. 382, 389; Herodotus v. 67-68, vi. 92, ix. 28; Thucydides i. 108, III ; iv. 7o, 101 ; v. 52, 82 ; Xenophon, Hellenica, iv., vi., vii. ; Diodorus xviii. I 1, xx. 102 ; Pausanias ii. 5-11; W. M. Leake, Travels in the Morea (1830), iii. pp. 351-381; E. Curtius, Peloponnesos (Gotha, 1851) , ii. pp. ; American Jour nal of Archaeology, V. (1889) pp. 267-303, viii. (1893) pp. 288-400, xx. (19o5) pp. 263-276; L. Dyer in the Journal of Hellenic Studies (1906), pp. 76-83 ; for coins, B. V. Head, Historia Numorum (1887), PP. also NUMISMATICS, section Greek, § "Patrae—Sicyon."