The Greeks of Crimea (and later of the adjacent Azovian region; present-day Donetsk Oblast, Ukraine) were represented by two groups: the Hellenic-speaking Romaioi, whose dialect is known as "Rumeíka", a.k.a. Mariupol Greek, and the Turkic-speaking Urums (also called Graeco-Tatars). These Byzantine Greeks of Crimea are Pontic Greeks who colonised Crimea. Both groups populated the region over the course of many centuries and consist of both the descendants of the ancient (4th century BC – 4th century AD) Greek and Byzantine Christian Greek colonizers of the northern shores of the Black Sea and interior of southern Russia and Ukraine and also of Pontic Greeks who fled as refugees or 'economic migrants' from northeastern Anatolia between the fall of the Empire of Trebizond to the Ottomans in 1461 and the 1828-29 Russo-Turkish War. However, the Greek settlers of the Crimea region underwent social and cultural processes, which led to them adopting the Crimean Tatar language as a mother tongue.