The Indo-Greek relations look back on 4000 years of intertwined history.
In Afghanistan, Pakistan and Northern India, several isolated Greek kingdoms managed to survive for 200 years after the conquests of Alexander the Great. Numerous cities founded by Alexander kept the Greek language and commerce with Europe alive even after the loss of rule in Asia. The succeeding kingdoms of Muslims and Indians profited from this. More than 40 Greek kings ruled over this region until the Baktric Dynasties were conquered in 130 BC.

In 143 BC, the Greek empire in Europe fell and was integrated into the Roman Empire.
330 AD Byzantium (the later Konstantinopel and Istanbul) became the capital of the Empire.

The Greek language, then Ancient Greek, remained a spoken and written language throughout. The Greek language had a similar function to the English nowadays during the Roman, Byzantian and Ottoman empires, it was an international language that allowed for transnational commerce. Even under Ottoman rule, the Greek language remained an important ingredient in the linguistic diversity of the region, and was partially important for the identification of religion, ethnicity, or as an expression of education and status.
Bactria (today Northern Afghanistan) stabilized the region, and built and secured the famous Silk Route, the more than 1000-kilometer-long “highway of commerce” between Asia and Europe.
The commercial language in the region remained Greek, which explains the linguistic allusions in Romanes. Main trade goods and numbers are almost identical in Greek and Romanes up until today.