Seleucus I Nicator was a Macedonian Greek general, a Diadochi of Alexander the Great and ultimately king who fought for control over his empire after his death. Having previously served as an infantry general under Alexander the Great, he eventually assumed the title of basileus and established the Seleucid Empire, one of the major powers of the Hellenistic world, which controlled most of Asia Minor, Syria, Mesopotamia, and the Iranian Plateau until overcome by the Roman Republic and Parthian Empire in the late second and early first centuries BC.
After the death of Alexander in June 323 BC, Seleucus initially supported Perdiccas, the regent of Alexander's empire, and was appointed Commander of the Companions and chiliarch at the Partition of Babylon in 323 BC. However, after the outbreak of the Wars of the Diadochi in 322, Perdiccas' military failures against Ptolemy in Egypt led to the mutiny of his troops in Pelusium. Perdiccas was betrayed and assassinated in a conspiracy by Seleucus, Peithon and Antigenes in Pelusium sometime in either 321 or 320 BC. At the Partition of Triparadisus in 321 BC, Seleucus was appointed Satrap of Babylon under the new regent Antipater.