The current national borders of Southeast Asia were not established until after World War II. What is now northern Vietnam was ruled by China for more than a thousand years, between the second century BCE and the tenth century CE. Then, in the 1800s, France conquered a region including the modern nations of Vietnam, Cambodia, and Laos. France did not withdraw from “Indochina,” as the region was called, until 1954.
In the map shown here, present-day Vietnam is divided into three regions: Tonkin in the north, Anam in the middle, and Cochin China in the south.