Aratus assembled his army in Sicyon. The majority waited on the road between Sicyon and the Acrocorinth, while Aratus himself went to the city with a select force of 400 men. Eight were sent forward to overwhelm the guards before 100 soldiers scaled the walls with ladders. Each was barefoot to minimise noise. They encountered a group of guards on entering the city, and killed three. But a fourth escaped and raised the alarm. Aratus and his soldiers got as far as the citadel itself, attempting to scale its walls as defenders hurled projectiles down on them. In the meantime, 300 more soldiers had scaled the outer walls, but then struggled to find Aratus inside the city. The waiting Achaean army below was at risk of being trapped between the citadel's defenders and a group of Macedonian soldiers arriving from the city, but was saved by those 300 soldiers, who were able to attack and rout the Macedonians from behind. The 300 men then went back to support their commander at the citadel. Weather conditions proved favourable for Aratus: