Through the
Partition of Babylon in 323BC, a compromise was reached under which Perdiccas was to serve as the "Regent of the Empire" () for the disabled Philip III and infant Alexander IV, as well as the supreme commander ('''') of the imperial army. Perdiccas soon showed himself intolerant of rivals and, acting in the name of the two kings, sought to hold the empire together under his own hand. Perdiccas oversaw the distribution of
satrapies to the other generals, sending away officers who threatened his authority. Perdiccas also attached
Cleomenes of Naucratis to Ptolemy in Egypt as a lieutenant. Modern historians believe this was done to limit Ptolemy's power and keep a watch on his actions. The men who remained at court with Perdiccas were probably those he could trust: his brother Alcetas, his brother-in-law Attalus,
Seleucus, and Aristonous. Alexander the Great's second wife,
Stateira, was murdered by Perdiccas, possibly at the urging of Roxana. Perdiccas also procured Alexander's "Last Plans" through the help of Eumenes, read the plans out before the army, and rejected them. This was done because not only were the plans extraordinarily expensive and grand (they included, for example, the conquest of all of
North Africa and the powerful
Carthaginian Empire, along with the construction of a fleet of a thousand
warships), but also because Perdiccas probably did not want to anger
Antipater by replacing him with
Craterus. Alexander's wife Roxana gave birth (in the late summer or early fall of 323BC) and Perdiccas assumed the guardianship of
Alexander IV.
Rebellions and refusals As his authority was unstable, possibly as early as the Siege of Babylon Perdiccas had negotiated a marriage with
Nicaea of Macedon, the daughter of Antipater, to ally himself with the viceroy, acknowledging Antipater's rule in Europe while improving his own position in Asia.
Bactrian Greek revolt During the winter of 323BC 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. In response, Perdiccas tasked
Peithon, another of Alexander's and satrap of
Media, with quelling it, and sent orders for the eastern satraps to contribute troops as well. Peithon marched east leading 3,800 men, with 10,000 to come from the eastern satraps. Although ancient sources suggest Peithon intended to recruit the Greeks and betray Perdiccas, modern historians dispute this. When the armies met, the Greeks surrendered and were partially slaughtered by Peithon's army. Perdiccas' motive in this affair is not clear; some traditions say he gave the order for the massacre in order to ensure Peithon did not gain an army or to punish the rebels, while another hypothesis is that the slaughter of the Greeks may have occurred through the actions of Peithon and was later blamed on Perdiccas.
Conquest of Cappadocia Despite success in the east, Perdiccas' authority as regent was then challenged in the west. Here, Perdiccas had appointed
Leonnatus, another , as satrap of
Hellespontine Phrygia on the western coast of
Asia Minor. At the Partition of Babylon, Perdiccas' supporter Eumenes was given the satrapies of
Cappadocia and
Paphlagonia, but both were unconquered. 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. Perdiccas probably gave Eumenes 5000
talents of gold for the reconquest of Cappadocia, allowing Eumenes to hire mercenaries. , and its regions. Perdiccas moved into
Cappadocia, then
Cilicia, and then
Pisidia in his successful restabilizing of the peninsula.|alt=A color map of Anatolia, with its various regions marked with black text Antigonus refused Perdiccas' order. Leonnatus accepted, mustering an army and marching to Cappadocia, arriving in the spring of 322BC. Leonnatus, however, received a letter from Macedon from
Cleopatra, Alexander the Great's full sister, and Antipater, both asking him to come west. Cleopatra, probably influenced by her mother
Olympias, offered herself as Leonnatus' bride, which would give Leonnatus claim to the Macedonian throne. Meanwhile Antipater asked Leonnatus for urgent assistance, as the former was besieged at
Lamia by the Greeks led by
Leosthenes, who were rebelling against Macedon in the
Lamian War. Leonnatus told Eumenes of his plan to head west, attempting to convince him to join; Eumenes refused and departed to Perdiccas' court, informing him of Leonnatus' intentions. For this information, Perdiccas elevated Eumenes to the ruling council of the Empire. This incident may have been what made Perdiccas "regard Cleopatra as a means of gaining supreme power". Upon learning of Leonnatus' departure, in the early summer of 322BC Perdiccas marched with the imperial army towards
Asia Minor to reassert his dominance as regent, install Eumenes in Cappadocia, and confront Antigonus. It also allowed him to "complete the conquest of Alexander's empire" as Alexander had ignored Cappadocia. In a single campaigning season, Perdiccas defeated the Achaemenid satrap of Cappadocia
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. This greatly contributed to Perdiccas' prestige; Perdiccas took Ariarathes captive,
tortured and killed him, and apparently
impaled most of his family. Perdiccas ordered Leonnatus to appear before him to stand trial for disobedience, but Leonnatus died during the
Lamian War before the order reached him. At some time during the first year of his reign, Perdiccas crowned Alexander IV as king alongside Philip III.
Conquest of Pisidia, Isauria, Larandia , minted in
Gaziura, dated 333–322BC. Perdiccas' defeat and execution of the 82 year old Ariarathes, along with his other conquests in Asia Minor, brought him to the height of his power.|alt=A color photograph of a silver coin on a white background. The front shows a Greek god sitting on a chair with a bird on his right hand, the back shows two horned animals Having settled Cappadocia, Perdiccas planned to send Eumenes to subdue the
Satrapy of Armenia, which was being mismanaged by
Neoptolemus. He marched with Eumenes to Cilicia in the autumn of 322BC and added the formidable and elite Macedonian
Silver Shields. The Silver Shields were some of the oldest and most experienced veterans of Alexander's conquests. Perdiccas then gave Eumenes his orders, and marched to
Pisidia. The native
Isaurians and
Larandians living here had revolted, murdering Alexander's satrap. Perdiccas campaigned against them next, easily conquering and destroying their cities in "short and brutal struggles", acquiring great amounts of
plunder and prestige; "Victorious in the field ... Perdiccas now enjoyed his greatest success".
Marriage and war To strengthen his control over the empire when his authority was weak, Perdiccas had agreed to marry Nicaea, the daughter of
Antipater, the regent of Macedon. But now, in the winter of 322–321BC, with his position greatly strengthened, Perdiccas was reconsidering the engagement. Furthermore, Olympias, the mother of Alexander the Great, offered him the hand of Cleopatra of Macedon, who was residing at
Sardis. Eumenes urged Perdiccas to marry Cleopatra, while Perdiccas' brother Alcetas advised marriage to Nicaea. Alcetas' faction believed that Perdiccas, in control of the royals, imperial army, and treasuries, could afford to wait for Antipater's death (he was very old) instead of incurring his wrath; Eumenes' faction argued Perdiccas ought to begin to formally rule and that the dual kingship of Philip III and Alexander IV was a sham. Rejecting Nicaea here would begin war with Antipater; as Perdiccas had yet to deal with Antigonus, he married Nicaea for the time being. During this winter, Antipater, having subdued
Athens in the Lamian War, deferred the decision regarding the
Samian exiles to Perdiccas; they were allowed to return to Samos on Perdiccas' order.
Bid for kingship Perdiccas decided that he wished to win the Macedonian throne, and had designed a plan for this; marriage to Cleopatra, and the return of Alexander's body, his son (Alexander IV), and his brother (Philip III) to Macedonia with Olympias' approval which, combined, would have made him "invincible" and virtually guaranteed the kingship. Given the intellectual disability of Philip III and the limited acceptance of the infant
Alexander IV due to his mother being a Persian, the marriage in particular would have given Perdiccas a claim as Alexander's true successor as king, not merely as regent. Feeling "full of confidence and well able to handle all his rivals," Perdiccas set about planning his march on Macedon. At this time he also responded to communications from the Athenian orator
Demades and the
Aetolian League, plotting with them secretly to depose Antipater. Around this time,
Cynane, Alexander's half-sister and widow of the Macedonian King
Amyntas IV, arranged for her daughter,
Eurydice II, to marry Philip III. Perdiccas, knowing this marriage would undermine his control over Philip III, sent an army under his brother Alcetas to order Cynane to return to Macedon. Cynane refused, and Alcetas' army killed her. 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". Perdiccas' army was furious at Cynane's murder and effectively mutinied. This widespread discontent compelled Perdiccas to spare Eurydice II and marry her to Philip III after all, eroding his control over the royal family. Though Perdiccas was able to regain overall control, this incident seems to have demonstrated to him that "the marriage to Cleopatra, despite the risks involved, was essential if the empire was to remain intact". Eumenes, accordingly, was sent by Perdiccas to Cleopatra with gifts to discuss marriage once again, and plans were set in place for the marriage to go forward. Perdiccas had, in the meantime, ordered Antigonus to stand trial for insubordination (failing to help Eumenes in Cappadocia) and other charges. Antigonus was an entrenched and powerful satrap in Asia Minor; his refusal of Perdiccas' order undermined the authority of his government and Perdiccas wanted to rectify this. 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. Craterus and Antipater, having subdued most of Greece in the Lamian War, were infuriated by Antigonus' news and Perdiccas' ambitions. They suspended their plans for more campaigns in Greece and prepared to march into Asia and depose Perdiccas, beginning the First War of the Diadochi. == Civil war and invasion of Egypt==