added by archaeologs Classification of the eras of Korea by archaeologists and historians. The major divisions following the Palaeolithic are: Chulmun, 7000-1000 BC; Bronze Age, 700 BC-0 AD; Iron Age, 400 BC-300 AD; Proto-Three Kingdoms, 0 -300 AD; Three kingdoms, 300-668; United Silla, 668-935; Koryo, 935-1392; Yi, 1392-1910; Japanese Colonial, 1910-1945; Modern, and 1945-present.