Harpalus (Greek: Ἅρπαλος) son of Machatas was an aristocrat of Macedon and boyhood friend of Alexander the Great in the 4th century BC. Being lame in a leg, and therefore exempt from military service, Harpalus did not follow Alexander in his advance within the Persian Empire but received nonetheless a post in Asia Minor. Alexander reportedly contacted him with a demand of reading material for his spare time. Harpalus sent his King theatrical plays by Aeschylus, Sophocles and Euripides, the history of Philistus and odes by Philoxenus and Telestes.
Harpalus was also a charming rogue who absconded three times with large amounts of money. The first time he was forgiven and reinstated, only to abuse his trust again. In 324 BC Harpalus found refuge in Athens. He was imprisoned by the Athenians after a proposal of Demosthenes and Phocion, despite Hypereides' opposition, who wanted an immediate uprising against Alexander. Ecclesia after a proposal of Demosthenes decided the guarding of Harpalus' money, which were entrusted to a committee led by Demosthenes himself. When the committee counted the money, they found 350 talents, although Harpalus had declared that he had 700 talents. Nevertheless, Demosthenes and the other members of the committee decided not to disclose the deficit. When Harpalus escaped and fled to Crete, the orator faced a new wave of public uproar. Areopagus conducted an inquiry and its findings charged Demosthenes with mishandling 20 talents. In Demosthenes' trial in Heliaia, Hypereides, who was the main prosecutor, predicated that Demosthenes admitted having taken the money, but said that he had used it on the people's behalf and had borrowed it free of interest. The prosecutor rejected this argument and accused Demosthenes of being bribed by Alexander. Demosthenes was fined with 50 talents and imprisoned, but after a few days he escaped by the carelessness or connivance of some citizens and wandered in Calauria, Aegina and Troezen. It remains still unclear whether the accusations against him were just or not. In any case, the Athenians soon repealed the sentence and sent a ship to Aegina to carry Demosthenes back to the port of Piraeus.
According to Pausanias, "shortly after Harpalus ran away from Athens and crossed with a squadron to Crete, he was put to death by the servants who were attending him (in 323 BC), though some assert that he was assassinated by Pausanias, a Macedonian". The geographer also narrates the following story: " The steward of his money fled to Rhodes, and was arrested by a Macedonian, Philoxenus, who also had demanded Harpalus from the Athenians. Having this slave in his power, he proceeded to examine him, until he learned everything about such as had allowed themselves to accept a bribe from Harpalus. On obtaining this information he sent a dispatch to Athens, in which he gave a list of such as had taken a bribe from Harpalus, both their names and the sums each had received. Demosthenes, however, he never mentioned at all, although Alexander held him in bitter hatred, and he himself had a private quarrel with him."
Harpalus is featured in the historical novel Fire From Heaven by Mary Renault. In it, he is entrusted by his teacher Aristotle with the task of observing and recording the lives of wild animals. Renault speculates that this would explain some of the fantastic accounts in Aristotle's zoological writings as Harpalian hoaxes.