Refers to the period that coincided with the rule of the Ko family in Korea, from 37 BCE - 668 CE. During this period, kings and noblemen built thousands of tombs from P'yong-yang to Manchuria, containing vast quantities of funerary objects and frescoes illustrating everyday life. In the last quarter of the 4th century, Buddhism replaced Shamanism, and effigies of the Buddha of both metal and pottery became more widespread.