According to Alexander's biographer Arrian, Alexander's army met the Persians on the third day of May from Abydos. Alexander's second-in-command, Parmenion, suggested crossing the river upstream and attacking at dawn the next day, but Alexander attacked immediately. This tactic caught the Persians off guard. The Macedonian line was arrayed with the heavy phalanxes in the middle, and cavalry on either side. Alexander was with the Companions on the right flank. The Persians expected the main assault to come from Alexander's position and moved units from their center to that flank.