Wu-ti, the most enterprising emperor of the Han dynasty, was the first to push his military exploration into the Korean peninsula, and from 107 B.C. onward the northern parts of the peninsula were successively turned into Chinese provinces. This was the beginning of the infiltration of Chinese civilisation into those regions. Afterwards on account of the internal disturbances of the Chinese empire, her grip on the conquered provinces became a little loosened, but at the beginning of the third century A.D. a strong independent Chinese state constituted itself on the east of the river Lyao, and Chinese influence thereby once more extended itself vigorously over the northern half of the peninsula: a new province was added to the south. In the districts which had thus become Chinese provinces, not only were governors sent from China, but a number of colonists must also have settled there, so that through them Chinese civilisation continued to infiltrate more and more, though very slowly, into the peninsula. This infiltration lasted till the middle of the fourth century, when the Chinese provinces in the peninsula were overrun and occupied by the Kokuri or the Koreans properly so called, who came from the northeast, and by this invasion of the barbarians the progress of civilisation in the peninsula was for a time obstructed. Still there might have remained a certain number of the descendants of the older Chinese colonists, and it is possible that they still retained some vestige of the civilisation introduced by their ancestors. The history of the peninsula at this period may be well pictured by comparing it to the history of Britain with its lingering Roman civilisation at the time of the Saxon conquest. It is just at the end of this period that Japan came into close contact with the peninsular peoples.