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.