Four more important Greek cities are established on the Libyan coast region within two hundred years of Cyrene's founding: 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 are known as the Pentapolis (Five Cities).

Often in competition, they find cooperation difficult even when confronted by common enemies.

From Cyrene, the mother city and foremost of the five, derives the name of Cyrenaica for the whole region.

The Greeks of the Pentapolis resist encroachments by the Egyptians from the east as well as by the Carthaginians from the west, but in 525 BCE the army of Cambyses (son of Cyrus the Great, King of Persia), fresh from the conquest of Egypt, overrun Cyrenaica, which for the next two centuries will remain under Persian or Egyptian rule.

Alexander the Great is greeted by the Greeks when he enters Cyrenaica in 331 BCE.

When Alexander dies in 323 BCE, his empire is divided among his Macedonian generals.

Egypt, with Cyrene, goes to Ptolemy, a general under Alexander who takes over his African and Syrian possessions; the other Greek city-states of the Pentapolis retain their autonomy.

However, the inability of the city-states to maintain stable governments leads the Ptolemies to impose workable constitutions on them.

Later, a federation of the Pentapolis is formed that is customarily ruled by a king drawn from the Ptolemaic royal house.

The economic and cultural development of the Pentapolis is unaffected by the turmoil its political life generates.

The region grows rich from grain, wine, wool, and stockbreeding and from silphium, an herb that grows only in Cyrenaica and is regarded as an aphrodisiac.

Cyrene becomes one of the greatest intellectual and artistic centers of the Greek world, famous for its medical school, learned academies, and architecture, which includes some of the finest examples of the Hellenistic style.

The Cyrenaics, a school of thinkers who expound a doctrine of moral cheerfulness that defines happiness as the sum of human pleasures, also make their home here and take inspiration from the city's pleasant climate.

Ptolemy Apion, the last Greek ruler, bequeaths Cyrenaica to Rome, which formally annexes the region in 74 BCE and joins it to Crete as a Roman province.

Cyrenaica under the Ptolemies had become the home of a large Jewish community, whose numbers were substantially increased by tens of thousands of Jews deported there after the failure of the rebellion against Roman rule in Palestine and the destruction of Jerusalem in CE 70.

Some of the refugees made their way into the desert, where they became nomads and nurtured their fierce hatred of Rome.

They have converted to Judaism many of the Berbers with whom they mingle, and in some cases whole tribes re identified as Jewish.

In 115 the Jews raise a major revolt in Cyrenaica that quickly spreads through Egypt back to Palestine.

The uprising is put down by 118, but only after Jewish insurgents have laid waste to Cyrenaica and sacked the city of Cyrene.

Contemporary observers count the loss of life during those years at more than two hundred thousand, and at least a century will be required to restore Cyrenaica to the order and prosperity that had meanwhile prevailed in Tripolitania.

The Emperor Diocletian, as part of his reorganization of the empire in 300, separates the administration of Crete from Cyrenaica and in the latter forms the new provinces of Upper Libya and Lower Libya, using the term Libya for the first time as an administrative designation.

The Libyans are assigned to the eastern empire with the definitive partition of the Roman empire in 395; Tripolitania is attached to the western empire.

Christianity had been introduced among Libya's Jewish community, and it soon gains converts in the towns and among slaves.

Rome's African provinces are thoroughly Christianized by the end of the fourth century, and inroads have been made as well among the Berber tribes in the hinterland.

From an early date, however, the churches in Tripolitania and Cyrenaica develop distinct characteristics that reflect their differing cultural orientations.

The former comes under the jurisdiction of the Latin patriarch, the bishop of Rome, and the latter under that of the Coptic (Egyptian) patriarch of Alexandria.

In both areas, religious dissent becomes a vehicle for social revolt at a time of political deterioration and economic depression.

Cyrenaica, which had remained an outpost of the Eastern Roman Empire during the Vandal period, also takes on the characteristics of an armed camp.

Unpopular East Roman governors impose burdensome taxation to meet military costs, but towns and public services—including the water system—are left to decay.

Constantinople's rule in Africa will prolong the Roman ideal of imperial unity there for another century and a half, however, and prevent the ascendancy of the Berber nomads in the coastal region.