The term Hellenistic (derived from Έλλην Héllēn, the Greeks' traditional self-described ethnic name) was established by the German historian Johann Gustav Droysen to refer to the spreading of Greek culture over the non-Greek people that were conquered by Alexander the Great. According to Droysen, the Hellenistic civilization was a fusion of Greek and Near Eastern cultures. The main cultural centers expanded from mainland Greece, to Pergamon, Rhodes, Antioch and Alexandria.
Modern historians see the death of Alexander the Great in 323 BC as the beginning of the Hellenistic period. Alexander's armies conquered the eastern Mediterranean, Egypt, Mesopotamia, and the Iranian plateau, Central Asia, and parts of India. Following Alexander's death, there was a struggle for the succession, known as the wars of the Diadochi (Greek for successors). The struggle ended in 281 BC with the establishment of four large territorial states.
- The Ptolemaic dynasty in Egypt based at Alexandria;
- The Seleucid dynasty in Syria and Mesopotamia based at Antioch;
- The Antigonid dynasty in Macedon and central Greece;
- The Attalid dynasty in Anatolia based at Pergamum.
His successors held on to the territory west of the Tigris for some time and controlled the eastern Mediterranean until the Roman Republic took control in the 2nd and 1st centuries BC. Most of the east was eventually overrun by the Parthians, but Hellenistic culture held on in distant locations, like the Greco-Bactrian kingdom in Bactria, or the Indo-Greek kingdom in northern India, or the Cimmerian Bosporus. Hellenistic culture remained dominant in the Eastern part of the Roman Empire until its Christianisation and transition to the Byzantine Empire.
The end of the Hellenistic period is generally seen as 31 BC, when the kingdom of Ptolemaic Egypt was utterly defeated by the Romans at the Battle of Actium. Octavian (Augustus) defeated Marc Antony at Actium, as a result, Egypt's last ruler, Cleopatra, (circa 30 BC) committed suicide and her kingdom was annexed by Octavian.
- Tarn, William Woodthorpe; G. T. Griffith Hellenistic Civilisation 3rd ed. rev. (1963), World Publishing Co., Cleveland