Hellenistic Era, the period from the conquests of Alexander the Great (died 323 B.C.) to Roman subjugation of the Mediterranean world (Egypt, the last to be taken, annexed 30 B.C.). Alexander, a Macedonian, had adopted the culture of the Greeks, or Hellenes. The Greek tongue and Greek learning were spread throughout the conquered regions by Alexander and his successors, the rulers of the Antigonid, Ptolemaic, and Seleucid kingdoms, which are referred to collectively as the Hellenistic kingdoms. Alexandria, Egypt, was the major center of Hellenistic culture.