The Abkhazians or Abkhazes are a Northwest Caucasian ethnic group, mainly living in Abkhazia, a disputed region on the northeastern coast of the Black Sea. A large Abkhaz diaspora population resides in Turkey, the origins of which lie in the population movements from the Caucasus in the late 19th century. Many Abkhaz also live in other parts of the former Soviet Union, particularly in Russia and Ukraine. The Abkhaz language belongs to the isolate Northwest Caucasian language family, also known as Abkhaz–Adyghe or North Pontic family, which groups the dialectic continuum spoken by the Abaza–Abkhaz (Abazgi) and Adyghe ("Circassians" in English). Abkhazians are closely ethnically related to Circassians. Classical sources speak of several tribes dwelling in the region, but their exact identity and location remain controversial due to Abkhaz–Georgian historiographical conflict. There are also three subgroups of the Abkhaz people. The Bzyb (Бзыԥ, Bzyph) reside in the Bzyb River region, and speak their own dialect. The Abzhui (Абжьыуа, Abzhwa) live in the Kodori River region, and also speak their own dialect, which the Abkhaz literary language is based upon. Finally, there are the Samurzakan who reside in the southeast of Abkhazia. History of Abkhazia Some scholars deem the ancient Heniochi tribe the progenitors of the Abkhaz. This warlike people came into contact with Ancient Greeks through the colonies of Dioskourias and Pitiuntas. In the Roman period, the Abasgoi are mentioned as inhabiting the region. These Abasgoi (Abkhaz) were described by Procopius as warlike, worshippers of three deities, under the suzerainty of the Kingdom of Lazica. The Abkhazian view is that the Apsilae and Abasgoi are ancestors of the Abkhaz–Adyghe group of peoples, while the Georgian view is that those were Colchians (Kartvelians or Georgians). Lazica was a vassal kingdom of the Byzantine Empire throughout most of its existence. Later the independent Kingdom of Abkhazia was established and the region became a part of the Georgian cultural world.