The first war of the Diadochs, from 321 to 320 BC, was fought between the Diadochi of Alexander the Great for the division of his Empire. In 323 BC, Alexander died suddenly, leaving a huge Empire, which included a significant part of the Balkan Peninsula, the Aegean Sea basin and vast territories in Asia. The Empire, which Alexander united with force was a diverse territory that included the highly developed city-states of Greece, the semi-wild regions of Macedonia, the agricultural regions of the Nile, the steppes of Central Asia, and deserts of Persia.
After the death of Alexander, his unborn child could not take over administration of the Empire, and immediately the question arose about continuity of power. The leading roles belonged to Antipater, Perdiccas, Antigonus, Seleucus, Ptolemy, Lysimachus, and Eumenes. Disagreement immediately manifested itself between them. These disagreements became armed clashes, the result of which was an agreement that if Roxanne had a son, he would be recognized as the new king. The regent of the empire was Perdiccas.
In Babylon, an agreement was reached among the diadochi. The basis of this agreement was that the state of Alexander would be a single state. The Diadochi divided management of individual regions of the empire among themselves. Antipater received Macedonia, Greece, and Thrace. Perdiccas received Asia. Antigonus ruled Phrygia, Pamphylia, and Lykia. Eumenes got Paphlagonia and Cappadocia. Ptolemy got Egypt. Lysimachus received Thrace and Ionia. Â Seleucus got Babylonia. Unlike Alexander’s policy, which divided the administrative and military authorities of the satrapies from each other, the Babylonian agreement provided for their unification under the satrapies. There was much tension between the Diadochi. Perdiccas set out to strengthen his power in every possible way and limited the power of the satraps in the provinces.
Beginning of Hostilities
By the spring of 322 BC, Diadoch Leonnatus died in battle with the Greeks. Diadoch Craterus, leading his army, was on his way to Macedonia to help Antipater, who was fighting the Lamian War. Nothing prevented Perdicces from strengthening his authority. Ptolemy, who occupied Egypt, showed himself to be an intelligent and far-sighted ruler, improving the economy and prosperity of his province.
Perdiccas called a military council of his supporters. On the agenda was the question of Ptolemy, who had seized Alexander’s body, as well as the disobedience of Antipater and Craterus. Despite advice to attack Macedonia, Egypt was chosen as Perdiccas’ goal of military intervention. The justification was based on the fact that Ptolemy had significant military power.
In 321 BC, Perdiccas led his army against Egypt. The Aegean fleet remained to guard the Hellespont against a possible invasion from the Balkans, and Eumenes remained commander of the troops in Asia. At the same time, Antigonus and Craterus hastily concluded peace and quickly approached the Hellespont with their troops. Under the agreement with Ptolemy, Antipater and Craterus were to strike the rear of Perdiccus, and after his defeat, Craterus would receive Asia and Antipater, Europe.
The War in Asia
Eumenes watched the situation rapidly deteriorate. Senior Macedonian soldiers who were under his command were unhappy with the prospect of waging war with their compatriots and refused to join the battle. Antipater’s troops consisted of experienced and loyal veterans, and the army of Eumenes consisted mainly of recruits from Asia. For these reasons Eumenes retreated to Cappadocia to strengthen his army.
The authority of the Macedonian generals was sufficient, and Eumenes’ detachments readily crossed over to their side. Antipater and Craterus crossed to Asia Minor, demanded and received help from the Minor Asian Greek cities. Eumenes, who knew about it in time, ordered Neoptolemus to join him, but he had collected troops and spoke against Eumenes. In the battle that took place, Neoptolemus suffered complete defeat and fled to Craterus and Antigonus. Antipater moved with a small detachment of  troops to Cilicia, and Craterus, along with Neoptolemus, attacked Eumenes with a significant part of the army. In the battle, Eumenes defeated the enemy, killing Neoptolemus in a duel. Craterus was killed in the battle.
War in Egypt
Perdiccas with his army came to the borders of Egypt. Ptolemy had been accused of disobedience. The courage with which Ptolemy came to the court, his belief in his innocence, and the sympathy of the Macedonians towards him, led to the Macedonian army declaring him innocent. Despite this, the regent ordered the war to continue. To Perdiccus came the news of Eumenes’ victory and the regent, inspired by this, continued his campaign.
The troops of Perdiccus approached the Egyptian stronghold of Kamil and began an assault. The Egyptian troops, led by Ptolemy himself, bravely defended themselves. The bloody battle lasted all day, and, having achieved nothing, Perdiccus ordered an end to the assault. A significant number of the troops entered the river. The water level began to rise rapidly, which led the troops to panic. Detachments were scattered along the river, and many lost their weapons. Angry soldiers cursed Perdiccas. As a result, the soldiers and some commanders started a riot, refusing to obey. Seleucus and Antigen, burst into Perdiccas’ tent and killed him. Ptolemy, upon learning of these events, immediately appeared in the camp. Ptolemy made a speech that he was mourning the loss of the Macedonians, and that he had to draw weapons against his old comrades, and all the blame for the death of many Macedonians lies with Perdiccus. Ptolemy’s speech was received favorably by the army. He was offered the Empire instead of Perdiccas, but Ptolemy wisely refused it. Therefore, the regency was entrusted to Python, the satrap of Media.
Results of the War and the Treaty of Triparadisus
With the death of Perdiccas and the refusal of Ptolemy to take the regency, the idea of a single state had lost any traction. The satraps, having emerged victors in the war, gained even greater independence. The problems were not resolved with the Treaty of Triparadisus. Perdiccus had many supporters, a significant army remained with Eumenes. Soon, war broke out again.
Sources:
- Droisen I. History of Hellenism. – Rostov-on-Don
- World history in 24 tons – Minsk: Literature
- Plutarch . Comparative biographies . Eumenes