The Macedonians, especially Seleucus I and his son Antiochus I, have established the Seleucid Empire and founded great many Greek towns in the region of present Afghanistan, where the Greek language will become dominant for some time.

The paradox that Greek presence is more prominent in Bactria than in areas far closer to Greece can possibly be explained by past deportations of Greeks to Bactria.

For instance, during the reign of Darius I, the inhabitants of the Greek city of Barca, in Cyrenaica, were deported to Bactria for refusing to surrender assassins.

In addition, Xerxes also settled the "Branchidae" in Bactria; they were the descendants of Greek priests who had once lived near Didyma (western Asia Minor) and betrayed the temple to him.

Herodotus also records a Persian commander threatening to enslave daughters of the revolting Ionians and send them to Bactria.

However, these few examples are not indicative of massive deportations of Greeks to central Asia.

Considerable difficulties faced by the Seleucid kings and the attacks of Ptolemy II of Egypt give Diodotus, satrap of Bactria, the opportunity to declare independence (about 255 BCE) and conquer Sogdiana.

He is the founder of the Greco-Bactrian Kingdom.

The new kingdom, highly urbanized and considered as one of the richest of the Orient, is to further grow in power and engage into territorial expansion to the east and the west.

The newly declared King marries a daughter, born around 266 BCE, of Antiochus II Theos and wife Laodice I and has two children: Diodotus II and a daughter, born around 250 BCE.