Vorotynsk used to be one of the Upper Oka towns and seat of the mediaeval Princes Vorotynsky. It was first mentioned in the Ipatiev Chronicle under the year 1155. In 1480, Vorotynsk was the principal base of Russian operations against the Tatars during the Great standing on the Ugra river. The town is thought to have been situated slightly downstream from the confluence of the Oka and the Ugra Rivers. The village of Spas-on-the-Oka, which now marks the spot, is dominated by Saviour Vorotynsk Monastery, founded by one Prince Vorotynsky in the early 16th century. This long-deserted cloister is noted for two crumbling churches with pyramidal roofs, one dating from the 1560s and another from the 1640s. There are also two villages, New Vorotynsk and Old Vorotynsk, located just south-west from the modern town of Kaluga. The Upper Principalities (Russian: Верховские княжества) is a term traditionally applied in Russian historiography to about dozen tiny and ephemeral polities situated along the upper course of the Oka River at the turn of the 14th and 15th centuries. ... Vorotynsky was one of the most eminent Rurikid princely houses of Muscovite Russia. ... Events Frederick I Barbarossa crowned Holy Roman Emperor. ... Events March 6 - Treaty of Toledo - Ferdinand and Isabella of Spain recognize African conquests of Afonso of Portugal and he cedes the Canary Islands to Spain Great standing on the Ugra river - Muscovy becomes independent from the Golden Horde. ... Miniature in russian chronicle, XVI century The Great standing on the Ugra river (Великое cтояние на реке Угре in Russian, also Угорщина (Ugorschina in English, derived from Ugra)) was a bloodless standoff between Akhmat Khan, Khan of the Golden Horde, and Grand Duke Ivan III of Russia in 1480, which... Ока Length 1,500 km Elevation of the source  ? m Average discharge  ? m³/s Area watershed  ? km² Origin  ? Mouth  Volga River Basin countries Russia Oka (Russian: Ока́) is a great river in Russia, right confluent of Volga. ... Ugra is a river in Smolensk and Kaluga Oblasts in Russia, left tributary of Oka river. ... The rocket-like church at Ostrov near Moscow is considered typical for Boris Godunovs reign. ... Konstantin Tsiolkovsky State Museum of the History of Cosmonautics in Kaluga, built in 1967 Kaluga (Калу́га in Russian) is a city in central Russia on the Oka River 188 km southwest of Moscow, administrative center of Kaluga Oblast. ...