Origins: The ancestors of the Vietnamese probably originated from the Indonesian islands for those who will become the Chams, and both from the Indonesian islands and the Asian continent for the Viet people. The first settlements appear in the Red River valley around 12'000 BC; it may be that those people mastered agriculture before the populations of the Near East (although that's the source of debate among scholars). From then on, several prehistoric cultures would follow, sometimes coexisting for a while (the Bac Son and the Quynh Van), until the Dong Son culture, that would be in existence for some 800 years, from 500 BC to 300 AD circa.

The shaping of the Cham and Viet kingdoms (1st millennium AD): It was at this time that appeared the foundations of the two kingdoms that will together occupy, more or less, the territory of today's Vietnam and which opposition will shape the Ancient Vietnam's history. On one hand the Viets: traditionally, the formation of the first kingdom and the first dynasty, the Van Lang, is said to have happened around 2880 BC, a dynasty that would endure until a Chinese general defeated the new king who had established himself in the north, in 208 BC. Despite being Chinese, that general and the dynasty he established ruled the Viets in defiance of the newly established Chinese Han rulers until 110 BC when it became part of the Empire. It would be the beginning of a thousand years of Chinese domination. As a result, the Viets were a sinised people, using Chinese characters to write documents but also historical annals, and who imported from their powerful neighbor their traditions in education, administration and legislation. Little by little, however, the Viets will free themselves from the direct influence of China both politically and culturally, by using their own language, but that will be a slow process. Until the very end of the first millennium AD, written evidence about the Viets comes exclusively from China.

At the same time, in the South, heavily under Hindi influence, is created the kingdom of Champa (2nd century AD). Of the two kingdoms, Cham will be the first with a strong cultural identity with many elements borrowed from India, but also with a political organization that sees the Cham leaders uniting, willingly or not, under the rule of a "King of Kings". The Dynasty of that ruler pretended that they were the descendant of a mythical figure that had received great power from Siva himself. The Chams, by the 9th century AD, have become powerful enough that their neighbors, be them the Khmers, the Viets or the local tribes that have yet to adopt any kind of writing system, never really try to conquer them. But that will change with the rise of the Viets after the 10th century AD: the external pressures on the kingdom will then become so great that the last rulers won't have the resources to maintain that unity, and won't be able to avoid an internal fragmentation of the Cham kingdom.

Independence and rise of the Viets: The Viets saw in the loss of power of the Tang dynasty a unique possibility to gain independence from their northern neighbor: in 938, Ngô Quyên lead his people to victory and established the first dynasty of the Independence. But as soon as he died, the kingdom was divided into twelve Warlords who fought for supremacy; the victorious warlord established the dynasty of the Dinh, and became the first Viet emperor recognized unanimously by the historians. Although the kingdom known as Dai Cô Viêt had gained its independence, the emperor recognized the Chinese suzerainty and agreed to pay a tribute to ensure peace.

After his death, peculiar circumstances lead to the power ending in the hands of a general who will lead the Viets to victory against the Song troops that had tried to use a period of dynastic instability to their profit. The Chams also will try to attack the Viets, to no avail, which will start the tensions between the two kingdoms. As a result of his victory, the general will create the new dynasty, that of the Lê, under which the foundations of a strong national unity will be laid

The following, that of the Lý, went even further to transform the kingdom and enforce its unity: centralization of administration and establishment of Buddhism as the national religion (mainly due to the fact that their scholars had supported the Lý) are among the accomplishments under a dynasty that will last more than two centuries, until 1225 AD. In relations to the Chams, another important development is the spread of the Viets towards the South as the population increased. At the beginning of that expansion (first half of the 11th century AD), the Cham kingdom was in a political disarray. It's from 1050 that attempts to unify the country again are made from the south, but the north will remain divided, which will make the territorial progression of the Viêts towards the south easier, and even a brief unification under one King in the last decades of the 11th century won't stay that progression

Pressures from abroad: The 12th and 13th centuries AD are marked by the making and breaking of alliances between the Chams and the Viêts against the Khmers (12th century AD) and the Mongol invasions (13th century AD). But even during the times when both kingdoms are political allies, skirmishes frequently happen on both sides of the border. The Chams are especially daring when the Dai Viêt goes through a time of political instability that will lead to a change of dynasty (1225 AD). But the new emperor swiftly put an end to it in 1252 AD. Before long, Chams and Viêts need to form a new alliance against the terrible Mongol invaders, who had just conquered China. Despite two attempts with 500,000 and 800,000 men respectively, the Mongols won't succeed against the much smaller armies of Champa and Dai Viêt.

However, those battles won't be without dire consequences. Many people died, and there aren't enough people left to work in the fields, especially in the Dai Viêt. As if that wasn't enough, the Chams will soon attack the Viêts. A Viêt princess had been given away as a bride to the Cham king in exchange for two territories. But the king died soon, and the princess should have been burned at the side of her husband. But the Viêts organized her escape, which finally resulted in repeated attacks from Champa, which weakened considerably the Dai Viêt. Because of all the resources absorbed to resist the Chams, the government has to levy new taxes that anger a population already suffering from the previous war against the Mongols. Southern territories are lost. All this will lead to a new change of dynasty and the new emperor, from Chinese origins, uses his Chinese name,Hô, when acceding to the throne. It is enough to alert the Ming dynasty.

Before becoming the first emperor of the new dynasty, Lê Qui Ly was associated to the governments of the last Trân emperors, and had successfully promoted agrarian reforms and brought peace again to the country, winning the heart of the population. With the peace restored, the Viêts not only resisted to the Chams' attacks, they were gaining ground again. Afraid, the Chams asked China for help, and the Hô dynasty couldn't resist for long the invasion. The occupation lasted 20 years before a popular revolt evicted the Chinese in 1428. The leader, Lê Loi, became the new emperor under the name Lê Thái Tô. In 1472, he decided once and for all to put an end to the threat of Champa, and effectively destroyed its capital; that was to be the end of the Cham kingdom, even if the many Chams who lived in territories annexed by the Dai Viêt remained attached to their ethnicity.

But the new-found glory of the Dai Viêt will be short-lived. Lê Thái Tô's successors aren't able to follow in his footsteps, and before long, the country falls into chaos for many years, even if it continued its expansion until reaching the size it still has today

History of Vietnam@Wikipedia
History of Vietnam@Lonely Planet
History of Vietnam@Windows on Asia (Asian Studies)
D.G.E. Hall, "A History of Southeast Asia", St Martin's Press, New York, 1968
Anne-Valérie Schweyer, "Le Viêtnam Ancien", Guides Belles Lettres des civilisations, Paris, 2005