In 336 B.C., Alexander the Great became the leader of the Greek kingdom of Macedonia. By the time he died 13 years later, Alexander had built an empire that stretched from Greece all the way to India. That brief but thorough empire-building campaign changed the world: It spread Greek ideas and culture from the Eastern Mediterranean to Asia. Historians call this era the “Hellenistic period.” (The word “Hellenistic” comes from the word Hellazein, which means “to speak Greek or identify with the Greeks.”) It lasted from the death of Alexander in 323 B.C. until 31 B.C., when Roman troops conquered the last of the territories that the Macedonian king had once ruled.