Cyrene, the ancient Greek city (in present-day Libya) was the oldest and most important of the five Greek cities in the region and gave eastern Libya the classical name 'Cyrenaica' that it has retained to modern times.

Cyrene was founded as a colony of the Greeks of Thera, traditionally led by Aristotle (later called Battus) of Thera, about 630 BCE. Details concerning the founding of the city are contained in Book IV of the Histories of Herodotus. Cyrenaica became part of the empire controlled by the Ptolemies from Alexandria in Egypt and later passed to the Roman empire. Cyrene was the birthplace of Eratosthenes and there are a number of philosophers associated with the city including Callimachus, Carneades, Aristippus and Arete.

The inhabitants of Cyrene at the time of Sulla (c. 85 BCE) were divided into four classes: citizens, farmers, resident aliens, and Jews, who formed a restless minority. Lucullus was sent to Cyrene by Sulla to quell disturbances in which the Jews were taking a prominent part. In 74 BC Cyrene was created a Roman province; but, wheras under the Ptolemies Jews had enjoyed equal rights they now considered themselves oppressed by the autonomous Greek population. Cultural conflicts were exacerbated by the resurgence of Jewish nationalism and resentment of Hellenistic culture with which many Jews had accommodated. Tensions came to a head in the insurrection of the Jews of Cyrene under Trajan (117 CE). This was quelled by Marcius Turbo, but not before about 200,000 Romans and Greeks had been killed (Dio Cassius, lxviii. 32). By this outbreak Libya was depopulated to such an extent that a few years later new colonies had to be established there, according to Eusebius.

Cyrene's chief local export through much of its early history - the medicinal herb silphium - was pictured on most Cyrenian coins, until it was harvested to extinction. Though commercial competition from Carthage and Alexandria reduced its trade, Cyrene, with its port of Apollonia (Marsa Susa), remained an important urban center until the earthquake of 365. Ammianus Marcellinus described it in the 4th century as a deserted city, and Synesius, a native of Cyrene, described it in the following century as a vast ruin at the mercy of the nomads.

Cyrene is now an archeological site near the village of Shahat. One of its more significant features is the Temple of Apollo which was originally constructed as early as 7th Century BCE. Other ancient structures include a Temple to Demeter and a partially unexcavated Temple to Zeus (the latter was intentionally damaged under orders of Moammar Al Qadhafi in summer 1978). There is a large necropolis approximately 10 kmē between Cyrene and its ancient port of Apollonia.

Cyrene is also mentioned in the New Testament: One Simon of Cyrene carried the cross of Christ (Mark 15:21 and parallels). See also Acts 6:9; 11:20; 13:1.