When Alexander came to Pamphylia in 333 BCE, Sillyon was the only place to resist him. Arrian the Nicomedian writes in The Anabasis of Alexander; "Having left a garrison in Side, Alexander advanced to Syllium, a strong place, containing a garrison' of Grecian mercenaries as well as of native barbarians themselves. But he was unable to take Syllium off hand by a sudden assault, for he was informed on his march that the Aspendians refused to perform any of their agreements, and would neither deliver the horses to those who were sent to receive them, nor pay the money; but that they had collected their property out of the fields into the city, shut their gates against his men, and were repairing their walls where they had become dilapidated. Hearing this, he marched off to Aspendus. "
Alexander's first improvised attack failed, and he abandoned the idea of a second.
Sillyum, situated between Aspendos and Perge in the west, stood on and around a flat-topped hill some 210 m high. All sides of the hill are precipitous except the W, and fortifications were needed only there. Occupation seems to have been originally confined to the flat hilltop, but later a wall was built on the SW slope to extend the inhabited area.
Sillyon, Antalya TR