Korea's myths and folklore are rooted in the ancient history of a land inhabited since Neolithic times. The earliest years are subject to myth with some references to the Gojoseon Kingdom being found in the northern region of Korea and Southern province of China in the 2300s BCE. Records become more reliable from the middle of the first millennium BCE before a 700-year stretch which is referred to as The Three Kingdom period before the ultimate domination of one of those Kingdoms, Silla, roughly at the time of the Viking Age in Europe and Scandinavia. Before long, though, the Mongol invasions of Korea in the 1200s overwhelmed the local rulers. Over 200 years later the Joseon Dynasty swept to power, heralding a golden era of independence, scientific and social development, and the creation of the Korean alphabet.