[1] The title of “Chúa” (chữ Hán: 主) in this context was comparable to the office of Shogun in Japan.

The Trịnh clan produced 12 lords who dominated the royal court of the Later Lê dynasty and ruled northern Vietnam for more than two centuries.

The founder of the clan was Trịnh Kiểm, who was born in what is now Vĩnh Lộc commune, Thanh Hóa province.

[citation needed] After her death, he joined the Lê loyalist army led by Nguyễn Kim.

In 1545, after the assassination of Nguyễn Kim, Trịnh Kiểm replaced his father-in-law as leader of the Lê dynasty's military and royal court.

[2] Despite the fact that the Mạc dynasty remained at large in the north, Trịnh Kiểm turned to eliminating the Nguyễn lords' power.

After seizing Tây Đô citadel and attacking Ninh Bình, on 20/5/1545, Dương Chấp Nhất invited Kim to visit his military camp.

Trịnh Tùng found out about this conspiracy, forcing Emperor Lê Anh Tông and his four sons to flee.

[citation needed] The historical victory of the Trịnh over the Mạc was a common theme in public Vietnamese theaters.

After the first offensive was beaten off after four months, the Nguyễn built two massive, fortified lines that stretched a few miles from the sea to the hills.

[citation needed] The Trịnh lords ruled reasonably well, maintaining the fiction that the Lê monarch was the emperor.

The key problem was a lack of land to farm, though Giang made the situation worse by his actions.

The reign of successor Trịnh Doanh was preoccupied with putting down peasant revolts and wiping out armed gangs that terrorized the countryside.

[citation needed] The Dutch East India Company ceased doing business with the Trịnh lords in 1700.

[4][5] The Trịnh lords started employing eunuchs extensively in the Đàng Ngoài region of the northern Red River delta area of Vietnam as military leaders.

Field army units, secret police, customs duty taxes, finance, land deeds and military registers and tax harvesting in son Nam province (Binh phien) as well as the position of Thanh Hóa military governor were delegated to eunuchs.

Using the popular rule of the regent as an excuse for intervention, in 1774, the hundred-year truce was ended and the Trịnh army led by Hoàng Ngũ Phúc attacked.

After Hoàng Đình Bảo's death, his subordinate in Nghệ An province Nguyễn Hữu Chỉnh defected to Tây Sơn.

Emperor Chiêu Thống did not want to reinstall Trịnh lords and rejected Lệ's request.

Generals Hoàng Phùng Cơ and Đinh Tích Nhưỡng also joined Bồng's faction and pressured Chiêu Thống to grant him the title prince, to which the emperor reluctantly agreed.

Nguyễn Hữu Chỉnh obeyed and marched north, where he defeated Trịnh army in Thanh Hoa Province.

Later, when the Qing army was occupying Thăng Long, Trịnh Bồng turned himself in to emperor Chiêu Thống.

After the Qing's defeat in early 1789, Bồng fled to the western region of the country, proclaimed himself to be a lord and built a resistance army against the Tây Sơn.

[8] After Gia Long founded the Nguyễn dynasty in 1802, he pardoned the Trịnh clan and allowed their descendants to worship their ancestors.

He gained thousands of converts, created a script for writing Vietnamese using a modified version of the European alphabet, and built several churches.

When the Nguyễn successfully used Portuguese cannon to defend their walls, the Trịnh made contact with the Dutch.

For a time, Dutch trade was profitable, but after the war with the Nguyễn ended in 1673, the demand for European weapons rapidly declined.

Unlike the Nguyễn lords who were happy to accept large numbers of Ming refugees into their lands, the Trịnh did not.

The unusual dual form of government they developed over two centuries was a creative response to the internal and external obstacles to their rule.

They lacked, however, both the power and the moral authority to resolve the contradictions inherent in their system of ruling without reigning.