Prince Fa Ngoum was born in 1316 at the Palace of Xieng Thong in the Kingdom of Muong Sua or Xieng Dong Xieng Thong. He was the son of Prince Khun Phi Fa. At that period, the Kingdom of Muong Sua was the theatre of complicated palace intrigues, due to rivalry among factions of the nobility.

At the age of 23, Prince Fa Ngoum, at the head of a group of close aids including palace officials, soldiers and servants, altogether 33 people, sailed on rafts down the Mekong River to the south. At the edge of Champa Nakhorn (Champassak) the Prince stayed and studied at the monastery of a venerable monk, Maha Pasaman. Then, he went to stay with Khmer King Jayavarman at Angkor Thorn and later married the King's daughter, Nang Keo Kanlayany.

At the Court of King Jayavarman at Angkor Thorn, Prince Fa Ngoum, thanks to his intelligence and wisdom, acquired the art of politics and strategy. However, his love for his native country was still ardent. He rallied forces from the southern towns to conquer the ancient Lao cities along the Mekong River with the aim of uniting them into a single kingdom.

Initial victories ( 1349-1353)

In 1351, Prince Fa Ngoum, accompanied by his wife, Nang Keo Kan1ayany, at the head of a ten thousand strong army, started a campaign under the motto "Conquering from smaller cities to larger ones". He started from Phra Viharn (Khao Phra Viharn), north of Angkor Thorn, and proceeded to Phimai on the west of Vat Phou, Champassak. After subduing the area, Prince Fa Ngoum took the principality of Sikhottabong (Thakhek), Champa Nakhorn, (Champassak) and returned to Sikhottabong to take over the neighbouring Viengphanamhoung-Xiengsa (Bolikhamxay) and Paksan.

Fa Ngoum then led his army to conquer Muong Phouan (Xieng Khuang), Sipsong Chu Thai (Nanoi Oinou, now Dien Bien Phu).

From there, he marched on to the Lue area of Sipsong Phanna in which he took over Bountai, Bounneua and Xieng Houng, the capital city of Sipsong Phanna. Moving down the Nam Ou River, Fa Ngoum and his army camped at Pak Ou to prepare for attacking Muong Sua or Xieng Dong Xieng Thong (Now Luang Prabang). Chao Fa Kham Khieo, the King of Xieng Dong Xieng Thong, sent his troops to fight those of Prince Fa Ngoum three times without success. Finally, the King abdicated. The people of Xieng Dong Xieng Thong then invited Prince Fa Ngoum to become the King of Lane Xang. He was crowned in 1353 under the name of Phanya Fa La Tholany Sri Sattana Khanahout.

The final victory and the unification (1354-1357)

In 1354, King Fa Ngoum prepared his troops to conquer territories in the Northwest, first of all the Kingdom of Lan Na (Xieng Saen). When Thao Ulong, the ruler of Xieng Saen, learned of the imminent attack by Fa Ngoum, he was scared. He sent a message to the King, saying: "I am the son of Nang Keo Mahaly. My mother is the daughter of King Kharnkhieo. We are related. Thao Ulong also sent a guard of honour and the population to welcome King Fa Ngoum.

After his victory in the territory in the northwest of the Mekong River, Fa Ngoum led his army to the central plains with the aim of taking Vieng Kham and Vieng Chan (Vientiane), two large principalities. He first attacked and took Xieng Kharn (Dan Sai) and then conquered Vieng Chan. From Vieng Chan, he crossed the Mekong River to take cities in the areas of Sukhothai and Ken Thao at the border with Ayudhaya. He installed his general quarters in Khorn Kaen for some time then returned to Vieng Chan to prepare for attacking Vieng Kham. After his victory in Vieng Kham, King Fa Ngoum took Roi Et and Khorat. He returned to Vieng Chan with his troops in 1357.

Just before that, King Fa Ngoum prepared to attack the principality of Lan Phya by sending a message to its ruler, Phanya Uthong laconically asking the latter: "Are you going to fight of what?" The frightened Phanya Uthong answered: "We are cousins as the descendants of King Khun Boulom. If you want territories, I shall give you some, from Dong Sam Sao (Dong Phanya Fai) to Phou Phanya Pho and the area of Nakhorn Thai. Moreover, I shall send you every year cane sugar and palm sugar. When my daughter, Nang Keo Lot Fa has grown up I shall send her to be at your service.

With courage and perseverance, intelligence and wisdom, King Fa Ngoum succeeded in unifying all the Lao territories by taking first the smaller and weaker cities, then, after forming a strong army, taking over larger principalities. After each victory, he installed a new administration in the subdued territory and offered mastership rights to the people.

The grand celebration of the victory

To celebrate the great victory in the unification of all Lao territories and to enhance his prestige and power over the nobility throughout the Kingdom of Lane Xang and the neighbouring kingdoms, King Fa Ngoum held a grandiose celebration, which lasted seven days and seven nights. It was organised in the end of 1357 in the Pak Passak area in the present Vientiane.

Addressing the participants, King Fa Ngoum said, among others "You all, who administer cities and territories, do not kill wrong doers. If their crime is not heavy, do not kill them. Put them in jail instead, accordingly with their crimes. Then, set them free so that they can find an occupation. As for the riches of this country, when there are people there will be riches. If there are no people you will find no riches indeed. That is the reason why I do not want you to kill. On the one hand, do not dispute or conflict one another. Together, keep the border of your territory. On the other hand, others will dispute our country, this must be clear to you…