Like the Phoenicians, Minoan and Greek seafarers had for centuries probed the North African coast, which at the nearest point lay 300 kilometers from Crete, but systematic Greek settlement there began only in the seventh century B.C. during the great age of Hellenic overseas colonization. According to tradition, emigrants from the crowded island of Thera were commanded by the oracle at Delphi to seek a new home in North Africa, where in 631 B.C. they founded the city of Cyrene. The site to which Berber guides had led them was in a fertile highland region about 20 kilometers inland from the sea at a place where, according to the Berbers, a "hole in the heavens" would provide ample rainfall for the colony.

Within 200 years of Cyrene's founding, four more important Greek cities were established in the area: Barce (Al Marj) Euhesperides (later Berenice, present-day Benghazi) Teuchira (later Arsinoe, present-day Tukrah) and Apollonia (Susah), the port of Cyrene. Together with Cyrene, they were known as the Pentapolis (Five Cities). Often in competition, they found cooperation difficult even when confronted by common enemies. From Cyrene, the mother city and foremost of the five, derived the name of Cyrenaica for the whole region.

The Greeks of the Pentapolis resisted encroachments by the Egyptians from the east as well as by the Carthaginians from the west, but in 525 B.C. the army of Cambyses (son of Cyrus the Great, King of Persia), fresh from the conquest of Egypt, overran Cyrenaica, which for the next two centuries remained under Persian or Egyptian rule. Alexander the Great was greeted by the Greeks when he entered Cyrenaica in 331 B.C. When Alexander died in 323 B.C., his empire was divided among his Macedonian generals. Egypt, with Cyrene, went to Ptolemy, a general under Alexander who took over his African and Syrian possessions the other Greek citystates of the Pentapolis retained their autonomy. However, the inability of the city-states to maintain stable governments led the Ptolemies to impose workable constitutions on them. Later, a federation of the Pentapolis was formed that was customarily ruled by a king drawn from the Ptolemaic royal house. Ptolemy Apion, the last Greek ruler, bequeathed Cyrenaica to Rome, which formally annexed the region in 74 B.C. and joined it to Crete as a Roman province.

The economic and cultural development of the Pentapolis was unaffected by the turmoil its political life generated. The region grew rich from grain, wine, wool, and stockbreeding and from silphium, an herb that grew only in Cyrenaica and was regarded as an aphrodisiac. Cyrene became one of the greatest intellectual and artistic centers of the Greek world, famous for its medical school, learned academies, and architecture, which included some of the finest examples of the Hellenistic style. The Cyrenaics, a school of thinkers who expounded a doctrine of moral cheerfulness that defined happiness as the sum of human pleasures, also made their home there and took inspiration from the city's pleasant climate.

Data as of 1987