The First Diadoch War saw the first open fighting between the former generals of Alexander the Great. In the aftermath of his death, an attempt had been made to organise his empire (settlement of Babylon, 323 BC). This had seen Perdiccas, his clossest associate at the time of his death, appointed regent for Alexander’s incapable brother and infant son, Craterus appointed guardian of the monarch, a largely honorary role and Antipater left in command in Macedonia. Apparently less important were the appointments to the satrapies, effectively the governors of provinces in the Empire. Ptolemy was given Egypt, Antigonus One-Eye large parts of Asia Minor and Eumenes was given Cappadocia and Paphlagonia, two areas that still needed to be conquered.
Alexander’s successors can be seen as falling into two main camps – those who wanted to preserve the empire intact, and those who wanted to take control of individual parts of the empire in their own right. The first group was further divided into those who were loyal to Alexander’s family, amongst them Antipater and Eumenes, and those who wanted power for themselves, most prominently Perdiccas and Antigonus.
The First Diadoch War was triggered by the ambitions of Perdiccas. After the settlement of Babylon, Perdiccas, who still had command of a sizable Macedonian army, had helped Eumenes conquer Cappadocia and Paphlagonia. He had done this without the help of Antigonus, who as a neighbouring satrap should have offered his assistance. In the aftermath of his victorious campaign in Cappadocia, Perdiccas summoned Antigonus to explain his absence and to provide accounts for his provinces. Alarmed, Antigonus fled to Macedonia to join Antipater.
One of the most distinctive features of the Hellenistic age was the rise in the importance of dynastic politics. The personal lives of the successors soon came to play a critical role in their political lives. This tendency can be seen very clearly in the events that led to the first open breach between Alexander’s generals. Antipater had offered his three daughters in marriage to the three most important successors – Perdiccas, Craterus and Ptolemy. All three accepted the offer, Perdiccas then received a more interesting offer, from Alexander’s sister Cleopatra. As Alexander’s posthumous brother-in-law, Perdiccas would have had a reasonable claim to the Macedonia throne. For a time he was undecided as to who to marry, but after Antigonus fled to Macedonia (late 322 BC), Perdiccas was engaged to Cleopatra, and possibly even married her.
The battle lines were now clear. In Macedonia an alliance was formed between Antipater, Craterus and Antigonus. They were joined by Lysimachus, who as satrap of Thrace controlled the land route between Greece and Asia Minor. Ptolemy too now declared against Perdiccas, by the dramatic gesture of seizing Alexander the Great’s funeral cortege and taking his body to Alexandria.
Perdiccas was left almost without significant allies. Only Eumenes of the better known successors remained on his side. However, he did have command of the Macedonian army in Asia. Perdiccas now split his forces. He led the expedition against Egypt, leaving Eumenes to defend Asia Minor against an invasion from Europe.
The Egyptian campaign could hardly have gone worse. The army reached the eastern branches of the Nile, but then became stuck in front of natural and man-made defences. After a disastrous attempt to cross the river, Perdiccas was murdered by his own officers. Ptolemy was then able to take command of the Macedonian army. The troops offered him Perdiccas’s role as guardian of the kings, but Ptolemy refused. His attention was already focused on an independent Egypt.
Ironically the murder of Perdiccas occurred before news of a great victory won by Eumenes reached the army. Eumenes had been unable to stop an army under Craterus from crossing the Hellespont, but when the two armies met in battle, probably somewhere on the borders of Cappadocia, Eumenes won. Craterus was killed in the battle. Two of the three most important of the successors had been killed within weeks of each other.
The murder of Perdiccas is seen as ending the First Diadoch War. Eumenes was isolated in Asia Minor. In 320 the remaining successors met at Triparadisus (Syria), to redistribute power in the empire. This new settlement would last no longer than the first. In 319 Antipater, possibly the last force for stability in the empire died, of old age, a genuine rarity amongst the successors, and the arrangements he had created at Triparadisus would collapse.