by the Qin and Han dynasties. During the prehistorical period, these three regions had their own style of inter-regional politics, culture and trades, which were relatively less affected by outside world. Recorded civilization dates to approximately 2000 BC in China's Shang Dynasty along the Yellow River Valley. Civilization expanded to other areas in East Asia gradually. In Korea Gojoseon became the first organized state approximately around 195 BC. Japan emerged as a unitary state with the creation of its first constitution in 604 AD. The introduction of Buddhism and the Silk Road were instrumental in building East Asia's culture and economy. Chinese dynasties such as the Sui, Tang and Song interacted with and influenced the character of early Japan and Korea. At the turn of the first millennium AD, China was the most advanced civilization in East Asia at the time and was responsible for the Four Great Inventions. China's GDP was likely the largest in the world as well. Japan and Korea had fully coalesced as centralized states in the regimes of Goryeo and Heian, The rise of the nomadic Mongol Empire disrupted East Asia, and under the leadership of leaders such as Genghis Khan, Subutai, and Kublai Khan brought the majority of East Asia under rule of a single state. The Yuan dynasty came to rule most of modern China and all of the Korean Peninsula. The Yuan dynasty also attempted and failed to conquer Japan in maritime invasions. The Mongol era in East Asia was short-lived due to natural disasters and poor administrative management. In the aftermath of the Yuan dynasty's collapse, new regimes such as the Ming dynasty and Joseon dynasty embraced Neo-Confucianism as the official state ideology. Japan at this time fell into feudal civil war known as the Sengoku Jidai which persisted for over a century and a half. At the turn of the 16th century European merchants and missionaries traveled to East Asia by sea for the first time. The Portuguese established a colony in Macau, China and attempted to Christianize Japan. In the last years of the Sengoku period, Japan attempted to create a larger empire by invading Korea only being defeated by the combined forces of Korea and China in the late 16th century. From the 17th century onward, East Asian nations such as China, Japan, and Korea chose a policy of isolationism in response to European contact. The 17th and