Philip who seems to have created charging cavalry. He caused his "companions" to drill for a massed charge. And also he strengthened his phalanx by giving the rear men longer spears than had been used hitherto, and so deepening its mass. The Macedonian phalanx was merely a more solid version of the Theban phalanx. None of these massed infantry formations was flexible enough to stand a flank or rear attack. They had very slight manœuvring power. Both Philip's and his son's victories followed, therefore, with variations, one general scheme of co-operation between these two arms. The phalanx advanced in the centre and held the enemy's main body; on one wing or the other the