History of the Cham–Vietnamese wars in the context of "Socialist Republic of Vietnam"

Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of Mainland Southeast Asia. With an area of about 331,000 square kilometres (128,000 sq mi) and a population of over 100 million, it is the world's 15th-most populous country. One of two communist states in Southeast Asia, Vietnam is bordered by China to the north, Laos and Cambodia to the west, the Gulf of Thailand to the southwest, and the South China Sea to the east; it also shares maritime borders with Thailand, Malaysia, and Indonesia to the south and southwest, the Philippines to the east, and China to the northeast. Its capital is Hanoi, while its largest city is Ho Chi Minh City.

Vietnam was inhabited by the Paleolithic age, with states established in the first millennium BC on the Red River Delta in modern-day northern Vietnam. The Han dynasty annexed northern and central Vietnam, which were subsequently under Chinese rule from 111 BC until the first dynasty emerged in 939. Successive monarchical dynasties absorbed Chinese influences through Confucianism and Buddhism, and expanded southward to the Mekong Delta, conquering Champa. During most of the 17th and 18th centuries, Vietnam was effectively divided into two domains of Đàng Trong and Đàng Ngoài. The Nguyễn—the last imperial dynasty—surrendered to France in 1883. In 1887, its territory was integrated into French Indochina as three separate regions. In the immediate aftermath of World War II, the Viet Minh, a coalition front led by the communist revolutionary Ho Chi Minh, launched the August Revolution and declared Vietnam's independence from the Empire of Japan in 1945.

Nam tiến (Vietnamese: [nam tǐən]; chữ Hán: 南進; lit. "southward advance" or "march to the south") is a historiographical concept that describes the historic southward expansion of the territory of Vietnamese dynasties' dominions and ethnic Kinh people (Đại Việt) from the 11th to the 19th centuries. The concept of Nam tiến has differing interpretations, with some equating it to Vietnamese colonization of the south and to a series of wars and conflicts between several Vietnamese dynasties and Champa Kingdoms, which resulted in the annexation and Vietnamization of the former Cham states as well as indigenous territories. The nam tiến became one of the dominant themes of the narrative that Vietnamese nationalists created in the 20th century, alongside an emphasis on non-Chinese origin and Vietnamese homogeneity. Within Vietnamese nationalism and Greater Vietnam ideology, it served as a romanticized conceptualization of the Vietnamese identity, especially in South Vietnam and modern Vietnam.

The Vietnamese domain gradually expanded from its original heartland in the Red River Delta into southern territories, which were controlled by the Champa kingdoms. In a span of some 700 years, the Vietnamese domain tripled the area of its territory and more or less acquired the elongated shape of modern-day Vietnam. Beginning in the 20th century, modern Vietnamese historiography, under the auspices of nationalism and racialism, coined the term Nam tiến for what they believed to be a gradual, inevitable southern expansion of Vietnamese domains. According to the 20th-century Vietnamese scholars who constructed the Nam tiến as a continuous historical phenomenon, the 11th to the 14th centuries saw battle gains and losses as frontier territory changed hands between the Viet and the Chams during the early Cham–Viet wars. In the 15th, 16th and 17th centuries, following the Fourth Chinese domination of Vietnam (1407–1427), the Vietnamese defeated the less centralized state of Champa and seized its capital in the 1471 Cham–Vietnamese War. From the 17th to the 19th centuries, Vietnamese settlers penetrated the Mekong Delta. The Nguyễn lords of Huế wrested the southernmost territory from Cambodia by diplomacy and by force, which completed the "March to the South".