Sometime between 1097 and 1155, the principality became a sovereign state and until 1161, according to the Hypatian Codex, the official name was the Muromo-Ryazan Principality. The first ruler of Ryazan was supposedly Yaroslav Sviatoslavich, Prince of Chernigov (a city of Kievan Rus'), later Prince of Murom-Ryzan. The capital of the Grand Duchy became Ryazan, however the present-day city of Ryazan is located 40 miles north from the original site of the capital today known as Ryazan Staraya (Old Ryazan). By the end of 12th century, the Principality waged wars with the neighboring Grand Duchy of Vladimir-Suzdal. In the course of that stand-off, the city of Ryazan was burned twice in a span of twenty years from 1186 to 1208. In 1217, there was a culminate point in history of Ryazan when during the civil war inside the Duchy six leaders of the state were killed by Gleb Vladimirovich who later defected to Cumans. Sometime around that time the Duchy came under a great influence from the Vladimir-Suzdal which was a factor in the fight of Ryazan to resume its sovereignty. In 1217, Gleb Vladimirovich with the support of Cumans tried to take Ryazan back out of the influence of neighboring northern principality of Vladimir, but he was defeated by another Ryazan prince Ingvar Igorevich who in turn became a sole ruler of the state.

In December 1237, the Duchy became the first of all other former states of Kievan Rus' to suffer from the Mongol invasion. The Duchy was completely overrun, with almost the whole princely family killed, the capital destroyed, and later moved to another location. In 1238, some of the armed forces of Ryazan withdrew to unite with the Vladimir-Suzdal army and meeting the forces of Batu Khan near Kolomna.

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