Libya Greek cities were established in the area that became known as Cyrenaica. In 525 BC the Persian army of Cambyses II 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 BC, and Eastern Libya again fell under the control of the Greeks, this time as part of the Ptolemaic Kingdom. After the fall of Carthage the Romans did not immediately occupy Tripolitania (the region around Tripoli), but left it instead under control of the kings of Numidia, until the coastal cities
Names of the Greeks revolved around Roman imperial rights. Unable to deny that an emperor did exist in Constantinople, they sufficed in renouncing him as a successor of Roman heritage on the grounds that Greeks have nothing to do with the Roman legacy. In 865, Pope Nicholas I wrote to the Emperor Michael III: "You ceased to be called 'Emperor of the Romans' since the Romans, of whom you claim to be Emperor, are in fact according to you barbarians." Henceforth, the emperor in the East was known and referred to in the West as "Emperor of the Greeks" and their land as "Greek