Mạc Đăng Dung, famed for his strength and cunning, had gotten got his start around 1506 as a bodyguard for the cruel and reviled Lê Emperor of Dai Viet, Lê Uy Mục.

Despite the deaths of several emperors, Mạc Đăng Dung had increased his power over time and gained many supporters.

However, he had also gained the enmity of other rivals for power.

A civil war starting around 1520 will last, with occasional breaks, for the next one hundred and fifty years.

The young Emperor, Lê Chiêu Tông, apparently fearing the growing ambition of Mạc Đăng Dung, fled to the south.

A revolt had begun, with the Trịnh and the Nguyễn families claiming to support the Emperor against the power of Mạc Đăng Dung.

Mạc Đăng Dung had responded by proclaimed the Emperor's younger brother, Prince Xuan, was now the true Emperor and installed him as Emperor under the name Lê Cung Hoàng.

The revolt had ended, temporarily, when Mạc Đăng Dung's forces captured and executed Lê Chiêu Tông along with the leaders of the revolt.

Mạc Đăng Dung in 1527 had removed the figurehead Emperor he had installed earlier and proclaimed himself as the new Emperor under the title Minh Đức.

This usurpation of the throne from the rightful Lê Emperors was not well received by the officials in the government.

Some were killed, some committed suicide, and some have fled to the south to join a new revolt by the Trịnh and the Nguyễn families against the Mạc Emperors.

A new revolt had begun, and both sides try to pull in allies, mainly the Ming dynasty but also King Phothisarat I of Lan Xang (modern-day Laos).

Mạc Đăng Dung, through submissive diplomacy and massive bribes, had persuaded the Ming not to attack in 1528, managing to obtain a temporary recognition of his rule.

He had abdicated his position as Emperor the following year in favor of his son, Mạc Đăng Doanh.

However, this had been done purely to solidify his son's claim to rule after he is gone.

In reality, Mạc Đăng Dung continues to rule with the title of Senior Emperor.

His son is not the equal of his father and as a result of several defeats, he has lost control of the provinces south of the Red River as the revolt has gathered strength.

The Nguyễn-Trịnh army in 1533 conquers the Winter Palace and proclaims Lê Trang Tông the rightful ruler of Vietnam.

The figurehead Lê emperor is officially crowned at the newly recaptured southern capital.

King Photisarath, one of the great kings of Lan Xang, had taken Nang Yot Kham Tip from Lanna as his queen as well as lesser queens from Ayutthaya, and Longvek.

Photisarath is a devout Buddhist, and has declared it as the state religion of Lan Xang.

In 1523 he had requested a copy of the Tripiṭaka from King Kaeo in Lanna, and in 1527 he had abolished spirit worship throughout the kingdom.

In 1532 the period of peace ended for Lan Xang when Muang Phuan rebelled; it will take Photisarath two years to fully suppress the rebellion.

In 1533 he moves his court to Vientiane, the commercial capital of Lan Xang, which is located on the floodplains of the Mekong below the capital at Luang Prabang.

Vientiane is the principal city of Lan Xang, and lies at the confluence of trade routes, but this access also makes it the focal point for invasion from which it is difficult to defend.

However, the move does allow Photisarath to better administer the kingdom and to respond to the outlying provinces that border the Đại Việt, Ayutthaya and the increasingly powerful Burmese polity.

The situation for Mạc Đăng Doanh turns desperate a few years later as an official Ming delegation reports that the Mạc rule is illegitimate and that the Lê should be restored to power.

As a result, in 1537 a huge Ming army comes down from the north with orders to defeat the Mạc.

In the summer of this year, Mạc Đăng Doanh dies and his father reclaims the throne.

Once again, Mạc Đăng Dung manages to send the Ming away by means of diplomacy (and bribes).

The Ming official position is that the Mạc should rule over the northern half of Vietnam, while the Lê should rule over the southern half (in other words, below the Red River).

The Ming army now returns home, but the Nguyễn and the Trịnh refuse to accept this division of the country and the war continues.

The Thai capture of Lovek, more than their conquest of Angkor a century and a half earlier, marks the beginning of a decline in Cambodia's fortunes.

One possible reason for the decline is the labor drain imposed by the Thai conquerors as they march thousands of Khmer peasants, skilled artisans, scholars, and members of the Buddhist clergy back to their capital of Ayutthaya.

This practice, common in the history of Southeast Asia, cripples Cambodia's ability to recover a semblance of its former greatness.

A new Khmer capital is established at Odongk (Udong), south of Lovek, but its monarchs can survive only by entering into what amounts to vassal relationships with the Thai and with the Vietnamese.

In common parlance, Thailand becomes Cambodia's "father" and Vietnam its "mother."

The Vietnamese—who, unlike other Southeast Asian peoples, have patterned their culture and their civilization on those of China—had by the late fifteenth century defeated the once-powerful kingdom of Champa in central Vietnam.

Thousands of Chams flee into Khmer territory.

By the early seventeenth century, the Vietnamese have reached the Mekong Delta, which is inhabited by Khmer people.

In 1620 the Khmer king Chey Chettha II (1618-28) marries a daughter of Sai Vuong, one of the Nguyen lords (1558-1778), who rules southern Vietnam for most of the period of the restored Le dynasty (1428-1788).

Three years later, Chey Chettha allows the Vietnamese to establish a custom-house at Prey Nokor, near what is today Ho Chi Minh City (until 1975, Saigon).

By the end of the seventeenth century, the region is under Vietnamese administrative control, and Cambodia is cut off from access to the sea

Trade with the outside world is possible only with Vietnamese permission.

The degenerated Le dynasty, which had endured under ten rulers between 1497 and 1527, in the end was no longer able to maintain control over the northern part of the country, much less the new territories to the south.

The weakening of the monarchy had created a vacuum that the various noble families of the aristocracy are eager to fill.

In 1527 Mac Dang Dung, a scholar-official who has effectively controlled the Le for a decade, had seized the throne, prompting other families of the aristocracy, notably the Nguyen and Trinh, to rush to the support of the Le.

An attack on the Mac forces led by the Le general Nguyen Kim results in the partition of Vietnam in 1545, with the Nguyen family seizing control of the southern part of the country as far north as what is now Thanh Hoa Province.

The Nguyen, who take the hereditary title chua, continue to profess loyalty to the Le dynasty.

By the late sixteenth century the Trinh family has ousted the Mac family and has begun to rule the northern half of the country also in the name of the Le dynasty.

The Trinh, who, like the Nyuyen, take the title chua, spend most of the seventeenth century attempting to depose the Nguyen

In order to repulse invading Trinh forces, the Nguyen in 1631 complete the building of two great walls, six meters high and eighteen kilometers long, on their northern frontier.

The Trinh, with one hundred thousand troops, five hundred elephants, and five hundred large junks, are numerically far superior to their southern foe.

The Nguyen, however, are better equipped, having by this time acquired Portuguese weapons and gunpowder, and, as the defending force, have the support of the local people.

In addition, the Nguyen have the advantage of controlling vast open lands in the Mekong Delta, wrested from the Khmer, with which to attract immigrants and refugees from the north.

Among those who take up residence in the delta are an estimated three thousand Chinese supporters of the defunct Ming dynasty, who arrive in 1679 aboard fifty junks and set about becoming farmers and traders.

The Nguyen, aided by the Chinese settlers, will succeed in forcing the Khmer completely out of the Mekong Delta by 1749.