Russian principalities

The Russian principalities (Russian: русские княжества), also known as the Rus' principalities (Ukrainian: Руські князівства), were polities that became independent following the disintegration of Kievan Rus' in the 12th century as a result of feudal fragmentation. During the 14th century the principalities of Southwestern and Southern Rus' were incorporated by the Kingdom of Poland and Grand Duchy of Lithuania. By the late 15th and early 16th century, the remaining Rus' principalities had been united with the Grand Principality of Moscow, leading to the creation of a centralized state. The period between the 12th and 15th centuries is also known as Appanage Russia.