Wikipedia
Vladimir-Suzdal (, Vladimirsko-Suzdal'skaya), also known as the Grand Duchy of Vladimir (1157–1331) (, Vladimiro-Suzdal'skoye knyazhestvo), was one of the major principalities that succeeded Kievan Rus' in the late 12th century, centered in Vladimir-on-Klyazma. With time the principality grew into a grand duchy divided into several smaller principalities. After being conquered by the Mongol Empire, the principality became a self-governed state headed by its own nobility. A governorship of principality, however, was prescribed by a Khan declaration ( jarlig) issued from the Golden Horde to a noble family of any of smaller principalities.
Vladimir-Suzdal is traditionally perceived as a cradle of the Great Russian language and nationality, and it gradually evolved into the Grand Duchy of Moscow.