《汉书·志·地理志上》
向东逐渐到达大海，向西覆盖到流沙，北方、南方一同波及，声威和教化深入到四海。
东渐于海，西被于流沙，朔、南洎，声教讫于四海。
Gradually reach the sea to the east, cover the quicksand to the west, and affect the north and the south together, and the prestige and education penetrate to the four seas.