The Greeks ( , i.e. “Hellenes”) are an ethnic group native to Greece, Cyprus, Anatolia, Southern Italy, South Caucasus, and other regions. They also form a significant diaspora, with Greek communities established around the world. Greek colonies and communities have been historically established in most corners of the Mediterranean and the Black seas, but Greeks have always been centered on the Aegean and Ionian seas, where the Greek language has been spoken since the Bronze Age. Until the early 20th century, Greeks were uniformly distributed between the Greek peninsula, southern Italy, the southern and western coasts of Asia Minor, the Pontic coast of the Black Sea, Cappadocia in central Anatolia, Cyprus, Egypt, with smaller communities in the Southern Caucasus and Georgia; many of these regions coincided to a large extent with the borders of the Byzantine Empire of the late 11th century and the Eastern Mediterranean areas of the ancient Greek colonization. The cultural centers of the Greeks were primarily the cities of Athens, Salonica, and Constantinople. Most ethnic Greeks live within the borders of the modern Greek state and Cyprus. A large-scale population exchange between Greece and Turkey ended the millennia-old Greek presence in Asia Minor and other parts of Anatolia. Other longstanding Greek populations can be found from southern Italy to the Caucasus and in the Greek diaspora communities in a number of other countries. Today, most Greeks are officially registered as members of the Greek Orthodox Church. Greeks have greatly influenced and contributed to culture, arts, exploration, literature, philosophy, politics, architecture, music, mathematics, science and technology, business, cuisine, and sports, both historically and contemporary.