The Greek presence in southern Russia is dated to the 6th century BC, although the ancient Greek settlers assimilated into the indigenous populations. The vast majority of contemporary Russia's Greek minority populations are descendants of Medieval Greek refugees, traders, and immigrants (including farmers, miners, soldiers, and churchmen/bureaucrats) from the Byzantine Empire, the Ottoman Balkans, and Pontic Greeks from the Empire of Trebizond and Eastern Anatolia who settled mainly in southern Russia and the South Caucasus in several waves between the mid-15th century and the second Russo-Turkish War of 1828-29.