ABOVE The crisis of the battle, Gaugamela, 1 October 331 BC. At this stage, the effect of Alexander’s dispositions and orders become clear. His refused right flank and his doubly refused left flank have the effect of stretching the Persian line, thinning the centre, and opening gaps. His tactical strike-force, the Companion heavy cavalry, then leads the Schwerpunkt, with support from the pike phalanx and the Hypaspists.