The Macedonian Antigonus I (382-301 B.C.), having served as a general under Alexander the Great, became the most powerful of his immediate successors.
Antigonus was born in Macedon, the son of the minor noble Philip. Nothing is known of his youth; he was 26 years older than Alexander and probably did not associate with him until Alexander became king. In 334 Antigonus campaigned with Alexander in Asia Minor; and after the conquest of its upland regions in the following year, Alexander appointed him satrap of Phrygia for his good service and military ability.
While Alexander marched on through Syria, Egypt, and Persia and into India, Antigonus remained in Asia Minor consolidating his satrapy. Consequently, when Alexander died 10 years later, Antigonus held his territory with greater power and authority than the other "successors," who scrambled for positions elsewhere.
Antigonus governed his kingdom well. In defending Phrygia against Persian partisans, Antigonus suffered the loss of an eye, which gave this tall Macedonian a rather ferocious appearance and gained him the nickname "Monophthalmos" (The One-Eyed). Antigonus ruled his domain with diplomacy and the constant awareness of the greatness of Greek culture and the freedom of the Greek cities in Asia Minor. This won for him the gratitude of the Greeks.
The years which followed Alexander's death were fraught with wars and political intrigues among the most powerful of Alexander's generals, including Antigonus. Alexander's counselor Perdikkas assumed the regency for Alexander's heirs, the half-witted epileptic Philip III Arrhedaeios, who was Alexander's half brother, and the posthumous son Alexander IV. Ptolemy gained control of Egypt and, in a fetishlike manner, of Alexander's body; Lysimachus became satrap of Greek Thrace but never obtained the political power Antigonus had developed in Phrygia; and Antipater continued to rule Macedon and Greece for the royal heirs as he had done earlier for Alexander.
Perdikkas had held the position closest to Alexander since Alexander's beloved Hephaestion had died; he also knew Alexander's last wishes. Perdikkas had persuaded the Macedonian troops in Babylon to await the birth of Alexander's child by the Persian Rhoxana and, if a boy, to elect by their feudal aristocratic methods the child as king. Perdikkas would assume the regency for the boy as grand vizier. Consequently, Perdikkas, as regent over Asia, sharply clashed with Antigonus in Asia Minor. Within a year Alexander's empire appeared to be divided between Antipater in Europe and Perdikkas in Asia. Although though Antigonus's satrapy was extended to include Pisidia, Pamphylia, and Lycia, Antigonus felt hemmed in.
Perdikkas sought to pacify the Asian borders, and he aided Eumenes, Alexander's secretary, in the conquest of the rebelling province of Cappadocia. Perdikkas also ordered Antigonus to send soldiers to help Eumenes, but Antigonus ignored the directive. Antigonus gathered in Europe the support of Antipater and Craterus against Perdikkas, whose ambitions to become king he suspected. Ptolemy also joined Antigonus's new coalition. Since Ptolemy had obtained Alexander's body against Perdikkas's wishes and now had joined Antigonus, Perdikkas in the spring of 321 struck out against Ptolemy's Egypt. Three attempts to cross the Nile Delta failed, and Perdikkas soon after was assassinated.
At the coalition's meeting at Triparadeisus, Antigonus was awarded the command of the royal army in Asia. In 320 Antigonus began several successful campaigns against the rebels Alcestas, who was Perdikkas's brother, and Eumenes.
Antigonus did not adhere to the agreements of the coalition very long, for he intended to obtain sole rule in Asia Minor and to expand his influence into Asia. In 319, when Antipater died, Antigonus alone of all the successor generals had the prospect of reuniting all of Alexander's empire.
Again in 318 Antigonus pursued Eumenes, who had built up a sizable force in Syria. Seleucus, whose power in Babylonia was weak, allied with Antigonus, but as Antigonus entered Syria and Babylonia, Seleucus found himself in a subordinate role and in 316 fled to Ptolemy's protection. Alexander's empire was now divided among Cassander in Macedon and Greece, Ptolemy in Egypt and Cyrene, Lysimachus in Thrace, and Antigonus in Asia from the Aegean Sea to the Indus Valley.
In 315 Ptolemy, Seleucus, and Lysimachus entered a coalition against Antigonus and began a 4-year war against him. Antigonus retained his power but lost Babylonia and the eastern satrapies in 311 to Seleucus. The short-lived treaty of 311 ended the hostilities. Although Antigonus did not emerge as victor, his prestige was enhanced. In 310 he invaded Babylonia unsuccessfully and retreated in 309. Ptolemy, meanwhile, secured Cyprus, invaded Cilicia, and agitated Greece and Athens against Antigonus, who finally struck back in 306. He gained Cyprus in June, when his son Demetrius I Poliorcetes defeated Ptolemy's fleet at Salamis. Though Antigonus and Demetrius now proclaimed themselves kings, they failed to subdue Ptolemy. By 302 Antigonus was master of Alexander's empire with the exception of Egypt.
In the spring of 301 Ptolemy and Lysimachus again challenged Antigonus, and in the ensuing war Antigonus died at the battle of Ipsus that same year. The victors divided his domain.
The formation of the Hellenistic kingdoms and the problems of Antigonus are discussed in Edwyn Robert Bevan, The House of Seleucus (2 vols., 1902); W. W. Tarn, Hellenistic Civilisation (1927; 3d rev. ed., with G.T. Griffith, 1952); and Pierre Grimal and others, Hellenism and the Rise of Rome (1965; trans. 1968).