Antigonus, now the dominant figure among the successors, occupies Syria and proclaims himself regent.

In order to win the support of the Greek city-states, whose resistance to subjugation presents the chief obstacle to the formation of a Hellenistic monarchy, he announces to his assembled army that all the Greeks shall be free, autonomous, and ungarrisoned.

This political slogan is to be sounded repeatedly- almost immediately by Ptolemy (and for a final time by the Romans in 196).

In the resulting coalition war (315–311), Seleucus is made one of Ptolemy's generals.

Antigonus, in order to win the support of the Greek city-states, whose resistance to subjugation presents the chief obstacle to the formation of a Hellenistic monarchy, announces to his assembled army that all the Greeks shall be free, autonomous, and ungarrisoned.

This political slogan is to be sounded repeatedly—almost immediately by Ptolemy (and for a final time by the Romans in 196).

Seleucus in the resulting coalition war (315-311 BCE) is made one of Ptolemy's generals.

Thessalonike, half-sister to Alexander the Great, was born around 352 or 345 BCE.

King Philip II, to commemorate the birth of his daughter, which fell on the same day as the armies of Macedon and Thessalian league won the significant battle of Crocus Field in Thessaly over the Phocians, is said to have proclaimed, "Let her be called victory in Thessaly".

In the Greek language her name is made up of two words Thessaly and nike, which translate into 'Thessalian Victory'.

Her mother did not live long after her birth and upon her death Thessalonike appears to have been brought up by her stepmother Olympias.

In memory of her close friend, Nicesipolis, the queen had taken Thessalonike to be raised as her own daughter.

Thessalonike was, by far, the youngest child in the care of Olympias.

Her interaction with her older brother Alexander would have been minimal, as he was under the tutelage of Aristotle in "The Gardens Of Midas" when she was born, and at the age of six or seven when he left on his Persian expedition.

She was only nineteen when Alexander, king of the then most known world, died.

Thessalonike had spent her childhood in the queen’s quarters, to whose fortunes she attached herself in 317 BCE when the latter returned to Macedon, and with whom she took refuge in 315 BCE, along with the rest of the royal family, in the fortress of Pydna, on the advance of Cassander.

The fall of Pydna and the execution of her stepmother threw her into the power of Cassander, who embraced the opportunity to connect himself with the Argead dynasty by marrying her; and he appears to have studiously treated her with the respect due to her illustrious birth.

This may have been as much owing to policy as to affection but the marriage appears to have been a prosperous one.

Thessalonike, as queen of Macedon, will become the mother of three sons, Philip, Antipater, and Alexander; and her husband pays her the honor of conferring her name upon the port city of Thessaloniki, which he founds on the site of the ancient Therma and twenty-six other local villages,.

The city, as it continues down to the present day, will soon becomes one of the most wealthy and populous cities of Macedonia, located at the head of the Gulf of Salonika in northern Greece, about one hundred and ninety miles (three hundred kilometers) northwest of Athens.

Antigonus is now in complete control of Asia Minor, but when he returns from the eastern provinces intending to reunite Alexander's empire under his own sovereignt, in 315 appointing himself the guardian of Alexander IV, he battles Cassander for dominance.

With the aid of his officers in Greece, Antigonus drives out Cassander's Macedonian forces of occupation and forms the island cities in the Aegean into the League of the Islanders, preparatory to his invasion of Greece.

His ally, the city of Rhodes, furnishes him with the necessary fleet.

Agathocles, the tyrant of Syracuse, seizes the city of Messene, present-day Messina, in 315 BCE.

The town of Agrínion iI Acarnania (west-central Greece), receives the assistance of Cassander, who helps the Acarnanians reorganize their defense league against Aetolian aggression.

Agathocles has embarked on a long series of wars.

His first campaigns (316 BCE to about 313 BCE), against the other Sicilian Greeks, have brought a number of cities, ...

…including Messana, under his control.

Carthage, fearing for its own possessions in Sicily, sends a large force to the island, thus renewing the struggle that has gone on between the Sicilian Greeks and Carthage intermittently since the sixth century.

Agathocles, tyrant of Syracuse, attacks the Carthaginians on their home turf, invading the shores of Africa in 310.

The Carthaginians, supported by Syracusan oligarchs opposed to Agathocles, quickly defeat the Syracusans at Licata and dispatch a separate army to besiege Syracuse.

Seleucus, returning his attention to his former province, Babylonia, in August 312 is able to reconquer Babylon with only a small army.

This conquest marks the beginning of the Seleucid era, which is dated Dios 1 (Oct. 7), 312, in the Macedonian calendar and Nisan 1 (April 3), 311, in the Babylonian calendar.

He establishes his imperial capital at Seleukeia on the Tigris, located just south of present Baghdad.