Page "Macedonian phalanx" Paragraph 4

Neither Philip nor Alexander actually used the phalanx as their arm of choice, but instead used it to hold the enemy in place while their heavy cavalry broke through their ranks.

The Macedonian cavalry fought in wedge formation and was stationed on the far right ; after these broke through the enemy lines they were followed by the hypaspists, elite infantrymen who served as the king's bodyguard, and then the phalanx proper.

The left flank was generally covered by allied cavalry supplied by the Thessalians, which fought in rhomboid formation and served mainly in a defensive role.