Macedonian Companion cavalry, known in Greek as the hetairoi, were the foremost shock troops of their age. Originally formed from the Macedonian nobility, esteemed friends and companions of their kings, these elite horsemen evolved under Philip II and Alexander the Great into a highly disciplined and formidable force with the adoption of the wedge formation that increased not only their manoeuvrability, but also their impact. Eventually their numbers were extended to include not just nobles, but in fact anyone who had been a friend to the king. Early Greek cavalry had been limited to skirmishing scouts and archers, as square formations of heavy cavalry up until this point were difficult to direct and wheel. However, the adoption of the wedge formation enabled the companions to exploit weak points or break the flanks of enemy infantry with precision. To achieve this they were armed with the 'xyston', a fearsome double-ended lance, designed to counter-balance itself and be reversible should one end break, plus a straight sword or curved kopis for close-quarters fighting. Armour took the form of a shaped bronze corselet, with optional greaves, and an open Boeotian helmet, which afforded some protection without hampering vision. The horse itself was unarmoured. The rider sat on a blanket, as neither saddle nor stirrups were used at this time.