Old Chosen

Around the 4th century B.C. the walled towns proceeded to combine with other walled towns into confederated kindoms such as Puyo in the Sungari river basin,  Old Choson ( 고조선 古朝鮮 Gojoseon ) in the Taedong river basin.Yemaek on the Yalu river and the state of Chin on the Han river .  Old Choson was the first state on the peninsula to appear in historical documents, is the Old Choson started as a  Principate of Chi-tzu who was a prince of the late Yan Dynasty of China.the most advanced of these was old Choson . According to legend, Dangun Wanggeom founded Old choson in 2333 B.C.. Modern historians generally consider Old Choson to have developed into a powerful federation or kingdom by around 4th century BC in the basins of the Liao and Taedong Rivers, ruling over northern Korean peninsula and southern Manchuria. Around 300 BC, Gojoseon lost significant western territory after a war with the Yan (  燕 ) state in China .Under pressure from the Chinese state of Yan, which invaded the Liaotung  Peninsula at the end of the 4th cent B.C., the Old Choson fell into a period of decline .