Alternative theories of the location of Great Moravia propose that the core territory of "Great Moravia", a 9th-century Slavic polity, was not (or was only partly) located in the region of the northern Morava River (in present-day Czech Republic). Moravia emerged after the fall of the Avar Khaganate in the early 9th century. It flourished during the reign of Svatopluk I in the second half of the century, but collapsed in the first decade of the 10th century. "Great Moravia" was regarded as an archetype of Czechoslovakia, the common state of the Czechs and Slovaks, in the 20th century, and its legacy is mentioned in the preamble to the Constitution of Slovakia.
Several aspects of its history (including its territorial extension and political status) are the subject of scholarly disputes. A debate about the location of its core territory began in the second half of the 20th century.[1] Imre Boba proposed that the center of Moravia was located near the southern Morava River (in present-day Serbia). Most specialists (including Herwig Wolfram and Florin Curta) rejected Boba's theory, but it was further developed by other historians, including Charles Bowlus and Martin Eggers. In addition to the theory of a "southern Moravia", new theories were proposed, arguing for the existence of two Moravias, called "Greater and Lesser Moravia", or arguing that the center of Moravia was at the confluence of the rivers Tisza and Mureș. Archaeological evidence does not support the alternative theories, because the existence of 9th-century power centers can only be documented along the northern Morava River, in accordance with the traditional view. However, scholars who accept the traditional view of a "northern Moravia" have not fully explained some of the contradictions between the written sources and archaeological evidence. For instance, written sources suggest a southward movement of the armies when mentioning the invasion of Moravia from the Duchy of Bavaria.