Artaxerxes, having rebuilt Persian power, combines forces with Phocion’s Athenian forces at Byzantium in 340—339 to oust Philip from Anatolia.

Philip's brother-in-law, King Alexander of Molossia (in Epirus, located in present Albania and northwestern Greece, with Illyria to the north, the Pindus mountains to the east, and the Gulf of Ambracia—near Préveza—to the south), around 340 unifies the Epirotes.

The Aetolian League has meanwhile become one of the leading military powers in Greece by about 340 BCE.

Praxiteles, the (presumed) son of the sculptor Cephisodotus, and a renowned Athenan sculptor in his own right, executes the magnificent Hermes and the Infant Dionysus around 340 for the Heraion at Olympia.

Discovered in 1877 in the ruins of the Temple of Hera at Olympia, it is displayed at the Archaeological Museum of Olympia.

It is traditionally attributed to Praxiteles and dated to the fourth century BCE, based on a remark by the second century Greek traveler Pausanias, and has made a major contribution to the definition of Praxitelean style.

Its attribution is, however, the object of fierce controversy among art historians.

The sculpture is unlikely to have been one of Praxiteles' famous works, as no ancient replicas of it have been identified.

The documentary evidence associating the work with Praxiteles is based on a passing mention by the second-century CE traveler Pausanias. (The Hermes’ sinuous curves and the fine finish of the marble conform to what is known of Praxiteles’ style.

Most scholars consider the famous sculpture to be an original work; others, however, characterize the Hermes as either an excellent Roman copy or a Hellenistic original by some follower of Praxiteles).

The Romans first occupy the site of Ostia, the harbor of Rome, around 340.

Located at the mouth of the Tiber River, seventeen miles (twenty-seven kilometers) downstream from the capital, it will guard the coast and serve as a naval base.

Several of the Latin cities, until now bound in a loose confederation with Rome, challenge Rome’s leadership and secede from the Latin League in 340.

The Campanians and other rebellious cities support them.

The vast fortified settlement of Kamenka on the Dnieper River, settled since the end of the fifth century BCE, has become the center of the Scythian kingdom.

A sovereign whose authority is transmitted to his son heads the Royal Scyths, rulers of the southern Russian and Crimean territories.

Eventually, the royal family had intermarried with Greeks, around the time of Herodotus.

The ninety-year-old ruler Ateas is killed while fighting Philip in 339.

Events in Thrace cause two of Philip’ of Macedon’s Greek allies, the cities of Perinthus (later called Heraclea, present-day Marmaraereglisi) and Byzantium, to review their position.

Consequently, Philip attacks Perinthus in 340 BCE.

Perinthus, which at this time seems to have been more important than Byzantium itself, is helped by Byzantium and other Greek communities, including Athens, and even by the Persian satraps (which represents the first collision between the two great powers, Macedon and Persia).

Despite all Philip's efforts (and artillery), Perinthus holds out.

He also switches his siege engines from Perinthus against Byzantium, to which Artaxerxes sends support also, but he makes no easy progress here either.

Athens having declared war on Macedon in 340, Phocion aids in the defense of Byzantium, but from about this time he regards the Macedonians as unstoppable and cultivates diplomatic relations with them in order to avoid outright conquest.

Artaxerxes, having rebuilt Persian power, combines forces with Phocion's Athenian forces at Byzantium in 340-339 to oust the Macedonians from Anatolia.

The declaration of war by Athens in 340 has enabled Philip to raise the two sieges without undue loss of face, though he has failed to establish a threat to the Athenian corn route to southern Russia.

It is possible that the reason for Philip's abandonment of at least the second of these sieges is not military (siege engines are now virtually irresistible when applied to their target over time) but political.

Philip's gaze is now fixed on Athens, the greater enemy and the greater prize.

Athens is to be intimidated now by invasion of its territory through central Greece, where the key position is held by Thebes, his ally hitherto, but of late a dissatisfied and recalcitrant one.

His services to it in the Sacred War have been more than offset by his new position as its successful rival for leadership in and through the Amphictyony, and his moves toward hegemony in Greece can be seen in Thebes as encroachments.

Philip, returning from his expedition against the Scythians, is refused passage through the territory of the Thracian Triballi people, now occupying the Haemus (Balkan) Range, unless they receive a share of his booty.

Philip forces a passage but is wounded in the hostilities.

The seventeen-year-old Alexander, left in charge of Macedonia in 340 during Philip's attack on Byzantium, meanwhile defeats the Maedi, a Thracian people of northern Macedonia.