The Vietnamese nation originated in the Red River Delta, in what is today northern Vietnam. As the nation became stronger, the Vietnamese expanded southward in a process known as nam tiến (literally "southward march"). This culminate in the incorporation of territories formerly belonging to Champa and part of the Khmer Empire into Vietnam, quite relatively recently in Vietnamese history. Along with the troops sent south, civilians were also sent to cultivate the land, and in their contact with the native Chams and Khmers, slightly different regional cultures began to emerge. At the same time, it is important to note that Vietnamese of all regions still share a general Vietnamese culture.
In the 17th and 18th centuries, Vietnam was ruled by a figurehead emperor of the Lê Dynasty. Actual power rested in the Trịnh lords in the North, called Đàng Ngoài (Outer Expanse) and Nguyễn lords in the South, called Đàng Trong (Inner Expanse). The two sides ruled their own domain independent of the other, and frequently fought each other. The imposed separation encouraged the two regions to develop their own cultures.
During French colonialism, the French divided the country into three parts, directly ruling over Cochinchina (southern Vietnam) while establishing protectorates in Annam (central Vietnam) and Tonkin (northern Vietnam). Consequently, Cochinchina was more directly influenced by French culture than the other two regions.
Between 1954 and 1975, the country was again divided. The North, ruled by a communist government, had contact and allied with communist China and the Soviet Union, while the South had an anti-communist, quasi-democratic government and had contact with the United States, the West and Western-aligned nations. North Vietnam had a state-planned command economy, which prohibited private enterprise and instituted a "Subsidy Program" nationwide in the 1960s, and conducted trade and economic relations with communist countries like China, the Soviet Union and Eastern Bloc. The Subsidy Program, later extended to the South after 1975, rationed and subsidized many basic goods, such as foodstuffs and fuel, so that all members of the general populace had a "guaranteed" limited supply of basic goods, as supplies for many common items were limited; items were purchased using a government-issued ration booklets. South Vietnam had a free market economy which conducted trade and economic relations with Western-aligned countries