We may without hesitation follow the opinion of Mommsen, who maintains that the limes was not intended, like Hadrian's Wall between the Tyne and the Solway, and like the great wall of China, to oppose an absolute barrier against incursions from the outside.
Four high roads radiate from Peking, one leading to Urga by way of Shan-hwa Fu, which passes through the Great Wall at Chang-kiu K`ow; another, which enters Mongolia through the.
Ku-pei K`ow to the north-east, and after continuing that course as far as Fung-ning turns in a north-westerly direction to Dolonnor; a third striking due east by way of Tung-chow and Yung-Ong Fu to Shan-hai Kwan, the point where the Great Wall terminates on the coast; and a fourth which trends in a south-westerly direction to Pao-ting Fu and on to Tai-yuen Fu in Shan-si.
It lies at the seaward end of the Great Wall of Trajan, and has evidently been surrounded by fortifications of its own.
Its ramparts are of stone, and its north rampart coincides with the great wall of Hadrian.
