The pezhētairoi (Greek: πεζέταιροι, singular: pezhētairos) were the backbone of the Macedonian army and Diadochi kingdoms. They were literally "foot companions" (in Greek the pezos means "foot warrior" or "infantryman", and hetairos means "companion" or "friend").

The Macedonian phalanxes were made up almost entirely of pezhetairoi. Pezhetairoi were very effective against both enemy cavalry and infantry, as their long pikes could be used to impale enemies charging on horse-back or to keep enemy infantry with shorter weapons at bay.

The pezhetairoi were the battalions of the Macedonian phalanx. They first came to prominence during the reign of Philip II, particularly when they played such an important role in Philip's subjugation of Greece at the Battle of Chaeronea in 338 BC. The name "foot companions" was used by famed commander Alexander the Great, the successor of Phillip II, as an ancient recruiting method. By labeling his infantry as his personal "companions" and "friends," Alexander was able to engage a wider manpower base for his subsequent military campaigns, as positions in his personal infantry would denote pride and honor. Therefore, as Alexander would campaign across Asia, he was able to use his reputation as a brilliant military strategist, along with the personal connotation given to his infantry, to recruit more native peoples to his cause than conventional recruitment methods of the day. This created a near endless base of manpower for the burgeoning military leader, and allowed him to engage in longer, costlier campaigns in areas like Asia Minor, Egypt, Persia, and India.

Pausanias of Orestis (Greek: Παυσανίας τῆς Ὀρεστίδος) was a member of Philip II of Macedon's somatophylakes, his personal bodyguard. He assassinated Philip in 336 BC, possibly at the instigation of Philip's wife Olympias, or even his son Alexander the Great. He was captured and killed. The most popular story explaining the murder comes from Diodorus Siculus, who expanded upon its mention by Aristotle. However Diodorus was writing over two centuries after Philip's reign, and without mentioning sources, thus his depiction must be taken with a grain of salt.

According to Diodorus, the general Attalus blamed Pausanias for the death of his friend. Philip and Pausanias had once been lovers, but the affair ended, and Philip started a new affair with Attalus' friend (also named Pausanias). The former Pausanias, feeling spurned, insulted his romantic rival in public. To secure his honor, Attalus' friend committed suicide by recklessly putting himself into danger in battle, while at the same time protecting the king. Devastated, Attalus sought to punish Pausanias of Orestis, and did so by getting the man drunk, and then submitting him to a rape. For any number of reasons, Philip did not punish Attalus. Pausanias of Orestis was promoted to the rank of somatophylax, probably as a consolation.