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.
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. In response, Perdiccas tasked Peithon, another of Alexander's somatophylakes 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.
Despite success in the east, Perdiccas' authority as regent was then challenged in the west. Here, Perdiccas had appointed Leonnatus, another somatophylax, 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.
Antigonus refused Perdiccas' order. Leonnatus accepted, mustering an army and marching to Cappadocia, arriving in the spring of 322 BC. 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 322 BC 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.
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 322 BC 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".
