The Hellenistic Period begins with the death of Alexander the Great at Babylon in 323 BCE and the division of his conquests among his generals, the Diadochi, into rival kingdoms, chiefly the Ptolemaic dynasty in Egypt, the Seleucid empire across Syria and Mesopotamia, and the Antigonid kingdom in Macedon and Greece. It ends conventionally with the Battle of Actium in 31 BCE and the Roman annexation of Ptolemaic Egypt the following year, the last major Hellenistic kingdom to fall, after the suicide of Cleopatra VII.
Across three centuries, Greek became the common administrative and literary language of a world stretching from Sicily to the Indus, a phenomenon historians call Hellenization, though it worked in both directions: Greek settlers and administrators absorbed local religious and intellectual traditions even as they spread their own. Alexandria in Egypt, founded by Alexander himself, became the period's greatest center of scholarship, housing its famous Library and Museum, while Hellenistic philosophy produced the Stoic, Epicurean and Skeptic schools that treated philosophy as a guide to living rather than pure speculation. Peter Green's From Alexander to Actium remains a standard narrative history of the period's political and cultural sweep.