The monograph provides a comprehensive analysis of the news of the Byzantine Emperor Constantine VII Porphyrogenitus and other written sources about the origin and settlement of the Croatian tribes, the ethnic history of the Slavic population of the Carpathian region. Taking into account the latest archaeological and linguistic data, the issues of the origin of the ethnonym “Croats”, the historical conditions of the Slavicization of its original bearers, and the Croatian ancestral home are being resolved. The geographical position of Greater Croatia, the territorial localization of the White Croats, and the routes of Croatian migration in the early Middle Ages are established.