1st millennium BC

From top left clockwise: The Parthenon, a former temple in Athens, Greece; Aristotle, Greek philosopher; Gautama Buddha, a spiritual teacher and the founder of Buddhism; Wars of Alexander the Great last from 336 BC to 323 BC; Letters of the Greek alphabet; People working during the Iron Age; Roman dictator, Julius Caesar is assassinated by the Roman Senate in 44 BC. (Background: A mural from the Assyrian Empire which dissolved in the 7th century BC) The 1st millennium BC, also known as the last millennium BC, was the period of time lasting from the years 1000 BC to 1 BC (10th to 1st centuries BC; in astronomy: JD 1356182.5 – 1721425.5). It encompasses the Iron Age in the Old World and sees the transition from the Ancient Near East to classical antiquity.

World population roughly doubled over the course of the millennium, from about 100 million to about 200–250 million after the birth of Jesus Christ and the establishment of the Julio-Claudian dynasty led by its founder Octavian.