Moravian Serbia (Serbian: Моравска Србија, Moravska Srbija) is the name used in historiography for the largest and most powerful state that emerged on the territory of the disintegrated Serbian Empire. The state was created in 1373, and attained its full extent in 1379, through military and political activities of its first ruler, Prince Lazar Hrebeljanović. The state comprised the basins of the Great Morava, West Morava, and South Morava Rivers.