After Alexander the Great died of a sudden illness in Babylon in 323 BCE, his generals initially attempted to preserve a unified empire by proclaiming Philip III Arrhidaeus and the infant Alexander IV as joint kings. However, actual power was held by regents like Perdiccas, to whom Alexander, on his deathbed, entrusted his signet ring. Perdiccas served as Chiliarch and managed state affairs to maintain central authority.
However, just two years after Alexander's death, the First War of the Diadochi erupted. It was driven by Perdiccas's attempt to consolidate power by marrying Alexander's sister, which united Antipater, Craterus, and Ptolemy against him. The conflict ignited when Ptolemy hijacked Alexander's funeral cortege, which was en route to Macedon for burial. Possessing the king's body was seen as a symbol of legitimacy, so Ptolemy diverted it to Egypt to bolster his own authority. Perdiccas invaded Egypt in retaliation but faced disaster when attempting to cross the Nile. Following this failure, he was killed in a mutiny by his own officers—Peithon, Antigenes, and Seleucus—triggering further fragmentation. The empire began to split as each general sought autonomy.
Following Perdiccas's death, Antigonus the One-Eyed was appointed Commander of Asia at the conference of Triparadisus. He was tasked with hunting down Perdiccas's remaining allies, most notably Eumenes. After defeating Eumenes, Antigonus emerged as the most powerful figure, controlling vast territories in Asia and the royal treasury. His rapid rise and ambition to rule the entire empire alarmed the other Diadochi—Lysimachus, Seleucus, Cassander, and Ptolemy—who formed a coalition to stop him.
Amidst these power struggles, the Argead royal family met tragic ends. In 317 BCE, Philip III Arrhidaeus was captured and executed by Olympias, Alexander the Great's mother, who sought to protect her grandson's rights. However, the young King Alexander IV and his mother Roxana were later imprisoned by Cassander. Around 310 BCE, Cassander ordered their assassination by poison or strangulation to eliminate the last legitimate heirs to the throne. With these deaths, Cassander declared himself King of Macedon.
As a direct confrontation against Antigonus's imperial ambitions, the climactic Battle of Ipsus in 301 BCE ended Antigonus’s ambitions; he was killed in battle, and the remaining territories were divided among the victors. Seleucus gained most of Asia, Lysimachus took western Anatolia, and Ptolemy kept Egypt.
The final major conflict arose when Seleucus defeated Lysimachus at the Battle of Corupedium in 281 BCE. However, Seleucus was soon assassinated by Ptolemy Ceraunus, a refugee he had harbored. Ceraunus, driven by the ambition to become King of Macedon, betrayed and murdered his benefactor. With this, the hope of reunifying Alexander's empire was lost forever. The vast empire permanently split into three main powers: Macedon in Europe, the Seleucid Empire in Asia, and the Ptolemaic Kingdom in Egypt.
