Riders were expected to steady themselves by holding on to the mane, but even this aid was no more essential than stirrups to an effective charge; Philip had recruited a force of Mounted Scouts who rode most usefully on reconnaissance and returned to charge in the front line with a lance so long that both hands were needed to hold it. They guided their horses by the pressure of their knees, like any expert modern horseman and far from being an idle experiment, their two-handed technique survived not only among Russian cavalrymen in Africa but also among the Scythian nomads of the south Russian steppes. What writing has done to the memory, stirrups have done to riding; without them, men simply had to grip harder and ride better than they mostly do nowadays.

There was, however, one technicality which helped the Companions to victory. Their basic unit was not a block but a wedge, shaped like a triangle, apex first. Cavalry have never been able to charge down a solid line of heavy infantry by a frontal attack, so the Companions first shattered or drew off the cavalry on the enemy's wing, then changed direction to cut diagonally into the flanks of the moving infantry in the centre. The wedge formation was pointed, and therefore more piercing, and it was adapted to diagonal changes of course 'because all the members fix their eyes on the squadron-leader at their point, like a flock of cranes which are flying in formation', and so took their cue from one conspicuous drill-master. Controlled turns were not easy even in a wedge. The Companions' reins and bridles were modern in appearance, but they could not be adjusted quickly to suit their circumstances, as the buckle did not exist; there were no curb-chains, so bits, especially the spiked 'hedgehog' variety, were very severe. The horses' mouths were hardened, therefore, and there were no martingales to keep their heads down when the bits were being pulled too hard. But Alexander still managed to lead with his Companions on the right wing, feint to the far right and pierce back into the centre in every pitched battle. The reason, surely, was the fluid wedge formation, which had been discovered by the brilliant horsemen of the barbarian Scyths and Thracians, and copied by Philip, who had repeatedly campaigned in the north against it,

The Companions punched and pierced on the right; the Foot Companions, in the centre, were designed for a solid follow-up. Some 9,000 in number, they were packed shoulder to shoulder in six brigades, the centre files of which seem to have been known as the Citizen Companions, a tide whose purpose is obscure. They were armed, memorably, to cause mass terror. They carried the Macedonian pike, or sarissa, a most extraordinary weapon; its longest variety was eighteen feet long, tipped at the point by a foot-long blade of iron and at the butt by the usual metal butt-spike which helped to balance it and allowed it to be rammed into the ground for a rest or for a guard against an enemy's frontal charge. It had to be held with both hands and like the cavalry lance, it was made of cornel wood, cousin of the dogwoods from which spits and skewers have often been cut for their hard grain. The cornel tree grows abundantly in several forms, not only on Macedonia's hillsides but also in Greece and the western hills of Asia which Philip planned to conquer; its most common form, Corn us mas, has deceptively slender branches of a wide-spreading and is nowadays admired by knowing gardeners for its primrose-yellow spring flowers. Probably Macedonian foresters pruned it so that it threw up stocky stems. They made up each sarissa's full length by joining two selected branches into a central tube of bronze which helped to balance the centre of gravity.

Because of the sarissa's length, the metal points of the first five ranks projected, perhaps in a graded series, beyond the Foot Companions' front line. It is uncertain whether the centre ranks also held sarissas or whether they were only included to give weight to the formation; they might be asked to fan out and broaden the front, so they probably did have sarissas too. If so, they could keep them vertical in deep formations and break the flight of enemy missiles, while the rear ranks could face about and drop their spears to the horizontal to make up a bristling rectangle. Drill had to be perfect, for the Foot Companions were a liability if they split, and the few known drill commands belie their years of complicated training. They could march in columns, rectangles or wedges, broaden their front by thinning their depth to a basic eight files or pack and narrow them to sixteen, thirty-two or even, in a crisis, a hundred and twenty. The file leaders were the most highly paid and seasoned troops in the unit. By marking time, they could wheel and advance at an angle, and by raising their sarissas vertically, countermarching or drilling round, then lowering them to the horizontal, they could face about. Against an enemy charge they would ram their sarissas into the earth and dress together to less than three feet between each man, so that the small shields strapped on their shoulders were contiguous. But they were never finer than when powering their way into infantry whom their cavalry had routed. Nobody who faced them ever forgot the sight; they kept time to their roaring of the Greeks' ancient war cry, Alalalalai;their scarlet cloaks billowed, and the measured swishing of their sarissas, up and down, left and right, seemed to frightened observers like the quills of a metal porcupine.

The button-shaped shield of the Foot Companions became the national emblem of Macedonians, and yet their unit may not have been wholly a Macedonian creation. Foot Companions had fought in files of ten before Philip's reign, and although it was he who introduced their sarissas and packed their formation in multiples of eight, it is very relevant that he had spent his youth as a hostage at the Greek city of Thebes, where the two boldest generals of the age, Epaminondas and Pelopidas, were already experimenting with the deep lines and slanting battlefronts which Philip and Alexander later favoured. As for the long pikes, they were compared with those of Homer's infantry, but a truer parallel lies in Egypt where the natives had always fought with long spears and wickerwork shields. In the past forty years, professional Athenian captains had been advising the pharaohs on their army, and one of them had doubled the length of his Greeks' spears as a result; another, Iphicrates, had done likewise for the open plains of Asia, and he was a well-known friend of the Macedonian royal family, especially of Philip's mother, whom he had served, probably soon after the Foot Companions were first recruited. Another Athenian professional, Charidemus, had often campaigned on Macedonia's borders, and it was from him that Philip is said to have learnt the tight shield-to-shield formation which the Foot Companions used on the defensive. But the city of Thebes was to be destroyed by its former visitor's army and Charidemus was exiled to Asia on Alexander's orders, where he advised the Persians against the troops whom he had once helped to teach.

Infantry armed with sarissas were every Greek state's ambition in the age that followed, and the Foot Companions became the most famous unit in Macedonia. But their formation was beset with difficulties, and those who saw them with Alexander knew it. In each of his big pitched battles, the Foot Companions either played little part or else split out of line on uneven ground, and before they invaded India, they gave up the sarissa altogether; they were a battle-winning force only if the cavalry shocked the enemy first, but they could not keep in step when the cavalry began to gallop, and once their wall of sarissas parted, through rough terrain or incompetence, the men inside were extremely vulnerable. Probably they had always worn metal greaves on their legs and breast-plates of leather or metal, an expensive but necessary defence against missiles, at least for the file-leaders; their helmets were made of metal too, and because both hands were busied with the sarissa their shields had to be small, some eighteen inches in diameter, and were slung by a strap across the left shoulder and upper arm. Often of bronze, they were convex in shape like a button, studded and painted with geometrical patterns; against heavy infantry they were a poor protection when the line had broken. Sarissas, of course, were almost useless in close combat, and the short daggers which Foot Companions wore on their hips were very much a last resort.