His attempt to marry Cleopatra of Macedon, Alexander's sister, which would have given him claim to the Macedonian throne, angered critical generals—including Antipater, Craterus and Antigonus—who decided to revolt against the regent in the First War of the Diadochi.

In response to this formidable coalition and a provocation from another general, Ptolemy, Perdiccas invaded Egypt, but his soldiers mutinied and killed him in 321/320 BC when the invasion foundered.

[14] As the commander of a battalion of the Macedonian phalanx (heavy infantry), in 335 BC Perdiccas fought in the Balkan campaigns of Alexander against the Illyrian peoples located northwest of Macedon.

[28] When Hephaestion unexpectedly died the same year, Perdiccas was appointed his successor as commander of the Companion cavalry and chiliarch, effectively becoming Alexander's second-in-command.

[35] The Roman historian Quintus Curtius Rufus provides Perdiccas' apparent speech to the assembly: For my part, I return to you the ring handed to me by Alexander, the seal of which he would use on documents as symbol of his royal and imperial authority.

Accordingly, since nothing remains of him apart from the material which is excluded from immortality, let us perform the due ceremonies to his corpse and his name, bearing in mind that the city we are in, the people we are among and the qualities of the leader and king of whom we have been deprived.

[38] Another of Alexander's companions, Ptolemy, proposed a joint board of generals to rule the Empire, perhaps as a slight against Perdiccas as such a scheme would greatly decrease his current authority.

[46][47] Meleager's powerbase began to diminish, and he was eventually convinced by Eumenes of Cardia, Alexander's former secretary, to reconcile with the generals, perhaps in collusion with Perdiccas.

[47] While the general Craterus was officially declared "Guardian of the Royal Family",[48] Perdiccas effectively held this position, as the joint kings were with him in Babylon.

[52] Through the Partition of Babylon in 323 BC, a compromise was reached under which Perdiccas was to serve as "Regent of the Empire" (epimelētēs) for the disabled Philip III and infant Alexander IV, as well as supreme commander (strategos) of the imperial army.

[56] This was done because not only were the plans extraordinarily expensive and grand (they included, for example, conquest of all of North Africa and the powerful Carthaginian Empire, along with the construction of a fleet of a thousand warships),[57] but also because Perdiccas probably did not want to anger Antipater by replacing him with Craterus.

[60] During the winter of 323 BC in the Upper Satrapies, specifically in Bactria (in modern day Afghanistan), a rebellion had begun consisting of 23,000 Greek mercenaries who had heard of Alexander's death and now wanted to return home.

[68] Perdiccas thus used his authority as regent of the joint kings to order Leonnatus and Antigonus (satrap of Phrygia, Pamphylia and Lycia) to aid Eumenes in securing his satrapy.

[74] Upon learning of this, in the early summer of 322 BC Perdiccas marched the imperial army towards Asia Minor to reassert his dominance as regent, install Eumenes in Cappadocia, and confront Antigonus.

[54][75] In a single campaigning season, Perdiccas defeated Ariarathes I and his large army (30,000 infantry, 15,000 cavalry) in two decisive pitched battles, capturing more than 5,000 soldiers and killing 4,000 others, allowing his supporter Eumenes to claim his satrapy.

[93] At around the same time, Cynane, Alexander's half-sister and widow of Amyntas IV, arranged for her daughter, Eurydice II, to marry the king, Philip III.

[95] Whether Perdiccas ordered this killing or not is debated, but it initiated a reversal of his ascendancy; "His officers grew increasingly suspicious of his aspirations, the common soldier was alienated by his acts of barbarity".

Though Perdiccas was able to regain overall control, this incident probably demonstrated to him that "the marriage to Cleopatra, despite the risks involved, was essential if the empire was to remain intact".

[98] In response Antigonus, fearing confrontation with the regent, fled to Antipater's court in Macedon, bringing news of not only Perdiccas' murder of Cynane, but his kingly aspirations and intention to marry Cleopatra instead of Nicaea.

[101][102][95] In late 321 and early 320 BC, as part of his kingly aspirations, Perdiccas intended to send Alexander's body back to Aegae in Macedonia, the traditional place of burial for the Macedonian Argead Royal Family.

[104][105] Ptolemy, who had already come to an understanding with Antipater and Craterus, had probably colluded with Arrhidaeus and Archon, satrap of Babylon in order to have Alexander's body go to Egypt.

[106] Perdiccas, enraged by this news, sent an army to recover the body, but Ptolemy defeated this force and successfully brought Alexander's remains back to Egypt, where they were housed in the city of Memphis.

[108] Perdiccas, who already distrusted Ptolemy, regarded his diverting of Alexander's body as an unacceptable provocation, "an act of war", and after convening his officers decided to invade Egypt.

[108][109] Perdiccas' strategy was for his supporters to hold Asia Minor against Antipater and Craterus while he brought the royal army, and kings (Philip III and Alexander IV), south to eliminate Ptolemy.

[113] Before Perdiccas left Pisidia, he attempted once more to entreat Cleopatra of Macedon to marry him, now needing the increased authority the marriage would bring, but she refused, not knowing who would win the war to come.

[112] Docimus conquered Babylon and killed Archon in battle, while Perdiccas reached Damascus and deposed Laomedon, satrap of Syria for Ptolemaic sympathies.

He travelled swiftly upstream to find a suitable point to cross, soon coming across a ford which led to the cities of Tanis and Avaris on the other side of the Nile.

[127] The fighting continued inconclusively for a considerable amount of time, with heavy losses for both sides, before Perdiccas finally broke off the siege and marched back to his camp.

News of Eumenes' victory at the Battle of the Hellespont in 320 BC where Craterus and Neoptolemus were killed, which would have instantly restored Perdiccas' authority, arrived in Egypt one day after his assassination.

[135][136] Anson notes that "if the news of Eumenes' victory over Craterus had arrived sooner, the entire history of the post-Alexander era might have been dramatically altered; Perdiccas might have emerged supreme, the successor of Alexander and the ruler of the vast Macedonian empire, with the inauguration of a new royal family".