We know nothing of Eumenes’ early life before he became a friend of Philip II of Macedon (342 BC) and then his secretary, apart from the fact that he came from Cardia, in the Thracian Chersonnese. Alexander the Great was sufficiently impressed by Eumenes’ services to his father to keep him on after Philip’s assassination in 336, promoting him to chief secretary.
Eumenes was given a military command during Alexander’s expedition to India (327-326). At one point when Alexander was in need of money to finance a sea expedition under the admiral Nearchus of Crete, he tried to borrow some from his commanders. He asked Eumenes for 300 talents, but Eumenes only contributed 100 talents, saying that even that much was a strain on his resources. Alexander didn’t believe him and secretly gave orders that Eumenes’ tent be set on fire to see how much treasure he would hurry to save. The plan backfired when all Eumenes’ records went up in flames. But, 1000 talents in melted gold and silver was found. Alexander didn’t take any of it, just wrote to his generals and governors asking them for new copies of the burnt documents.
Eumenes did not get on with Hephaistion, Alexander’s closest friend and second in command, but this does not seem to have affected Eumenes’ relationship with Alexander. Despite, or perhaps because of, this lack of cordiality between them, Eumenes was one of the most extravagant in his mourning for Hephaistion after his death (324), and this increased Alexander’s regard for him.
After Alexander’s death, Eumenes was appointed governor of Cappadocia, despite the fact that it didn’t actually belong to the Macedonians. Perdiccas, who by one account had been appointed regent for Alexander’s mentally defective brother and unborn son, ordered the generals Leonnatus and Antigonus to help Eumenes take possession of his territory (321). Antigonus refused to help, but Leonnatus came, more to inveigle Eumenes into helping him in his plan to seize power in Macedon than to help Eumenes himself.
Eumenes refused to help Leonnatus and quietly left the camp one night to join Perdiccas with the news of Leonnatus’ plans. Perdiccas used his army to help Eumenes take possession of Cappadocia. Once Eumenes was firmly in command, Perdiccas left him with orders to take possession of Armenia from Neoptolemus. Finding the Macedonian foot soldiers Perdiccas had left under his command difficult to deal with, Eumenes proceeded to build up his cavalry forces until they numbered 6,300 men.
When Antigonus and Antipater made an alliance against him, Eumenes was defeated by Antigonus, but managed to escape, and use his forces to harass Antigonus’ baggage train. Eumenes dismissed most of his men because he had too many to move about unnoticed but not enough to go on the attack.
He was besieged in Cappadocia with the remainder of his forces (about 500 cavalry and 200 foot soldiers) in a fortress called Nora. The fortress was well-stocked with basic provisions; the main problem was lack of space to exercise the animals. To prevent their condition from deteriorating, Eumenes rigged up a pulley system, which lifted the horses up until only their hind feet remained on the ground. In this position he forced them to jump and kick until they worked up a thorough sweat.
Eumenes and his forces spent the winter of 320-319 in Nora, but when spring came, he managed to escape with all his men while negotiating with Antigonus over terms for Eumenes and his men to join Antigonus now that Antipater was dead. Many of Eumenes’ men who he had dismissed before the siege rejoined him, bringing his forces back up to about a thousand cavalry.
Eumenes received letters from Olympias, Alexander’s mother, asking him to help her assert her authority in Macedon on behalf of Alexander’s son. He advised her to wait until the boy was old enough to rule, but she didn’t follow his advice, and seized power in Macedon. She then commissioned Eumenes to fight against Antigonus on her behalf, and wrote to the governors loyal to her, and Antigenes and Teutamus, the commanders of the elite force of the Argyraspids (the Silver Shields), ordering them to support him.
Because, as a non-Macedonian, Eumenes still faced some hostility and envy from the Macedonians, he announced that Alexander had told him in a dream to set up a council of leaders to meet daily in a special tent with an empty throne where Alexander himself would join them to guide their deliberations. Another way Eumenes used to safeguard himself against hostility was to borrow large sums of money from the people most hostile to him, hoping they would realise that if they killed him, they would never get their money back.
A recurring problem for Eumenes was that in winter (when campaigns were not usual) his soldiers tended to scatter with complete lack of discipline to pass the time wherever they wanted. Antigonus tried to take advantage of this fact in the winter of 317-316. He led his men on a ten-day march through the desert to attack Eumenes, choosing this route in the hope that his approach would remain a secret. Unfortunately, because of the cold in the desert at night, his men disobeyed him and lit fires to keep warm, thus giving the game away when they were still only halfway there.
However, five days was not enough for Eumenes to gather his scattered forces. He therefore ordered the troops he did have available to light huge fires in the mountains at night and to let them slowly die down, as was the usual practice in army camps, in order to convince Antigonus that the secret was out and Eumenes was waiting for him with a large army. Thinking that he was marching tired men suffering from the cold against a fresh army, Antigonus slowed down to let his men recover from the journey – and this delay was sufficient for Eumenes’ army to come together and win the battle.
This unexpected victory made the Macedonian leaders who were supposed be supporting Eumenes even more jealous. When, in another battle, Eumenes defeated Antigonus but lost his baggage train, Teutamus, the commander of the Argyraspids, entered into negotiations with Antigonus to get the baggage back. Antigonus agreed, provided that Eumenes was handed over to him alive. Teutamus agreed to this proposal, and the Argyraspids took Eumenes unawares and handed him over to Nicanor, Antigonus’ emissary.
Now that he had Eumenes as a prisoner, Antigonus was uncertain what to do with him. Nearchus of Crete, who had been Alexander’s admiral, proposed a forced retirement, but in the end those who wanted Eumenes’ death prevailed. Antigonus decided to starve him to death, but after two or three days, when Antigonus wanted to move camp, he had Eumenes executed and his body given to his family for a decent funeral.