Throughout Antiquity, the city was relatively unimportant. According to one legend, the city was founded as a colony from Argos, while another holds that it was founded, along with Side and Aspendos, by the seers Mopsos, Calchas and Amphilochus after the Trojan War. The city is first mentioned in c. 500 BC by Pseudo-Scylax ("polis Sylleion"). From 469 BC, the city (as Sillyon) became part of the Athenian-led Delian League. It is mentioned in the Athenian tribute lists in c. 450 BC and again in 425 BC, and then disappears again from the historical record until 333 BC, when Alexander the Great is said to have unsuccessfully besieged it. According to Arrian ("Anabasis Alexandri" I. 26), the site (recorded as Syllion) was well-fortified and had a strong garrison of mercenaries and "native barbarians", so that Alexander, pressed for time, had to abandon the siege after the first attempt at storming it failed.