Ryazan (ryəzänˈyə) [key], city (1989 pop. 515,000), capital of Ryazan region, E central European Russia, on the Oka River. Industries include oil refining, lignite processing, and the manufacture of machine tools and agricultural and transport equipment. The city has extensive piers, and river trade is carried on in agricultural products. One of Russia's oldest cities, Ryazan was founded in 1095 and became the capital of the Ryazan principality when the Mongols destroyed Old Ryazan in 1237. It was annexed by Moscow in 1521 and was called Pereyaslavl-Ryazan until 1778, when it became a city. Ryazan retains much medieval architecture and has picturesque churches with many-colored domes and gilded ornaments. A kremlin wall, dating from 1208, surrounds two former monasteries built in the 15th and the 17th cent. Ryazan has the Archangel Cathedral (late 15th–early 16th cent.) and the Uspenski or Assumption Cathedral (1693–99). The former archiepiscopal palace is now a museum.