Seleucus' territorial demands (e.g., the surrender of Cilicia and the cities of Tyre and Sidon) soon rupture the previously harmonious relationship with Demetrius, who has retained control of the sea.

The possession of Syria gives him an opening to the Mediterranean, and he immediately founds, as a chief seat of government, the new city of Antioch (modern Antakya, a city in Hatay province in southern Turkey) on the banks of the Orontes River about fourteen miles (twenty-two kilometers) from the Mediterranean at the end of the fourth century CE.

He names the city in memory of his father, Antiochus, and imports colonists from Athens and Macedonia, intending it to be a western counterbalance to his eastern capital of Seleucia.

Seleucus founds the city of Europos on the Euphrates River in Syria in 303 BCE.

The new city controls the river crossing on the route between his newly founded cities of Antioch and Seleucia on the Tigris.

Seleucus embarks in 305 BCE on an expansion of his kingdom throughout the Iranian east (the upper satrapies) as far as India, intent on recovering Alexander’s Indian province.

but his advance is eventually halted by Chandragupta (Greek Sandrokottos), the founder of the Maurya dynasty of India.

In a pact concluded by the two potentates, Seleucus agrees to territorial concessions in exchange for five hundred elephants.

By this time, Chandragupta controls the Indus and Ganges plains as well as far northwestern portions of the Indian subcontinent.

The citizens of Rhodes, following their defeat of Demetrius in 305, begin planning to erect a monumental thank offering to their divine patron Helios.

Cassander loses his other possessions south of Thessaly when …

…Sicyon, and …

…Argos in the Peloponnese.

Antigonus has founded several cities, especially in Asia Minor, and united several small communities into unitary, large centers: Lebedus (Lebedos) and Teos, for example.

Several Greek artists grace his court; Apelles had painted his portrait in profile because of his missing eye (the cause of which is unknown).

Now at the zenith of his power, Antigonus demands Cassander's unconditional submission.

He wants possession of Macedonia, the native land of his dynasty, and to establish his dominion over Alexander's former empire.

The other Diadochi, however, warned by Cassander's fate, now join forces to attack the 80-year-old potentate.

From Babylonia, Seleucus invades Asia Minor, Ptolemy attacks Syria, and Lysimachus moves into the western part of Asia Minor.

Docimus, the regent of Phrygia, and Phoenix, the strategos of Lycia, desert Antigonus.

He, in turn, recalls Demetrius, leaves Antigoneia, and crosses the Taurus Mountains.

Lysimachus, awaiting Seleucus, avoids an engagement.

In vain, Antigonus sends a corps of raiders into Babylonia in order to divide his enemies' forces.

Philetaerus, who had served under Antigonus in Phrygia, deserts in 302 to Lysimachus, who makes him guardian of the mountain fortress of Pergamon with its treasure of some nine thousand talents.

Achaea, …