Trịnh Kiểm (1503–1570) posthumously titled Thế Tổ Minh Khang Thái Vương (世祖明康太王), was an influential political and military figure of Đại Việt during the Southern and Northern Dynasties period.

Though his highest title during his lifetime was Thái Quốc Công (Grand Duke of the State), he is often regarded as the first Chúa (Lord) of the Trịnh family.

[5] He played a major role in organizing the Southern Dynasty’s government through key decisions such as establishing his headquarters in Vạn Lại[6], holding civil service examinations in Confucian studies, strengthening the military, recruiting talented individuals, repelling Mạc invasions in Thanh Hoa and Nghệ An–, reclaiming Thuận Hóa and Quảng Nam from Mạc control, and launching major northern campaigns.

Although he did not achieve a decisive victory over the Mạc, Trịnh Kiểm laid the foundation for his descendants to complete the restoration of the Lê Dynasty, reclaim Đông Kinh (modern-day Hanoi), and establish the long-lasting Lê-Trịnh era in Vietnamese medieval history.

When playing war games, Trịnh Kiểm and the village boys would arm themselves with knives and salt, then steal a buffalo from the Đầu Voi area in Yên Việt.

Among them was Nguyễn Kim, a powerful noble who retreated to the remote region of Cổ Lũng (modern-day Cẩm Thủy District) to plan an uprising against the Mạc, advanced his troops.

He assigned Trịnh Kiểm to oversee the farming estates in Thọ Liêu hamlet, where he was responsible for raising livestock, including buffaloes and horses.

During his daily routine, Trịnh Kiểm befriended a Cham man who also worked in the estate named Vũ Thì An, who was an expert in training horses.

:[9][5] [5] [10][10] Dissatisfied with his role and realizing that he had no real future of progression, one day Trịnh Kiểm stole the best horse from his master’s stables and fled.

His mother, however, who was left behind, fled back to their home village of Vệ Quốc knowing Ninh Bang Hau would be sworn with vengeance for this offense from a commoner.

He ordered his soldiers and the villagers of Sóc Sơn and Biện Thượng to hunt down Trịnh Kiểm and his mother no matter what, offering rewards for their capture.

Trịnh Kiểm quickly crawled through several layers of fences then fled to the home of a man named Nữu in Yên Định.

In gratitude for his past kindness, Trịnh Kiểm rewarded Nữu’s family with money for ancestral offerings and daily expenses.

Fearing that Mạc soldiers would desecrate her grave, he had Vũ Thì An and his son wrap the body in a mat and secretly transport it through the Đường Cán Mountains to a hidden burial site in Đồng Rạng (Yên Việt Village).

[11][5][12] After Mạc Đăng Dung usurped the throne, the descendants of Lê dynasty officials and loyal members, especially those from Thanh Hoa, refused to accept his rule and continuously rebelled.

The new emperor granted Nguyễn Kim the title Thái sư Hưng Quốc Công (Grand Mentor Duke).

From that day on, Nguyễn Kim appointed Trịnh Kiểm as Tri Mã Cơ a (Commander of the Cavalry), placing him in charge of the military’s horses.

According to “History of the Kingdom of Đàng Ngoài” by Alexandre de Rhodes, when Mạc forces launched a massive attack on the capital, Nguyễn Kim and his army found themselves trapped in an enemy siege.

Keeping his word, Nguyễn Kim married his daughter Ngọc Bảo to Trịnh Kiểm and assigned him more important military duties, especially the training of cavalry for the resistance forces.

Having heard of Trịnh Kiểm’s extraordinary prowess and commanding presence, Lê Trang Tông promoted him to Đại Tướng Quân (Grand General) and granted him the title Dực Quận Công (Duke).

The emperor viewed him as a trusted general, granting him the military seal and placing him in charge of battles against the Mạc dynasty in Thanh Hoa Province.

Later that year (1545), Emperor Lê Trang Tông granted Trịnh Kiểm an even higher title: “Đô Tướng Tiết Chế Các Dinh Quân Thủy Bộ Các Xứ Kiêm Tổng Nội Ngoại Bình Chương Quân Quốc Trọng Sự” (The Supreme Commander of All Land and Naval Forces, Grand Minister of State Affairs).He was also granted the noble rank of Thái Sư (Grand Mentor) and the title Lượng Quốc Công (Duke of Lượng).

In 1546, Trịnh Kiểm withdrew his troops to Thanh Hóa, established a temporary royal court for Lê Trang Tông in Vạn Lại, and began recruiting heroes and skilled warriors, training soldiers, stockpiling provisions, and strategizing for battles against the Mạc dynasty.

As a result, many warriors seeking glory, honor, prestige, from Hoan and Diễn (Nghệ An, Ô (Thừa Thiên, Huế), and Quảng (Quảng Nam, Đà Nẵng) flocked to join him, including notable figures such as Phùng Khắc Khoan, Lương Hữu Khánh, Đinh Bạt Tuỵ, Nguyễn Khải Khang, Nguyễn Thiến, and Lê Khắc Thận.

Afterward, Grand Chancellor Trịnh Kiểm appointed local leaders and officials to restore order, ensuring stability in the newly reclaimed lands.

The king agreed, granting Nguyễn Hoàng full control over Thuận Hóa, except for the requirement to send annual taxes to the royal court.

From this point on, Nguyễn Hoàng worked alongside Bùi Tá Hán, the governor of Quảng Nam, to defend the southeastern frontier of the Lê dynasty’s stronghold.

Thus, we must protect it at all costs and make it a solid defensive barrier… I have observed that Nguyễn Hoàng, is a composed and determined man, possessing both strategy and leadership.

I propose appointing him as the regional governor to maintain order at the frontier, defend against northern invaders, and coordinate with Trấn Quận Công in Quảng Nam to reinforce each other…”

Later that year, Nguyễn Hoàng traveled from Thuận Hóa to Thanh Hoa to visit the king and pay respects to Trịnh Kiểm.