1698 - 1706 H.M. Somdetch Brhat Chao Maha Sri Jaya Setha Adiraja Darmikaraja Chandrapuri Sri Sadhana Kanayudha [Sethathirat II] also called Ong Lo and Sai Ong Hue, Nephew of the great ruler Suliyavongsa, was the king of the Lao kingdom of Lān Xāng
He spent most of his early years as a prince of the royal house in exile at Hue (now in Vietnam) while his uncle King Suliyavongsa was King of Lanxang. His father Prince Som Phou fled to Vietnam upon the placement by the nobles of his younger brother Prince Suliyavongsa as King of lanxang.
Upon the death of King Suliyavongsa, a person of Noble blood but with no royal lineage named Tian Thala ascended to the thrown. Tian Thala was deposed by Prince Nan Tharat, 1695-1698 King of Lan Xang. King Nan Tharat the grandson of King Vickhsai (King of Lanxang 1637-1638). In 1698 Ong Lo attacked Vientiane, the capital of Lan Xang, and with the aid of Vietnamese forces ousted King Nan Tharat took the title name of King Sethathirat II and secured the city. In 1700 he declared himself king, and in 1705 he moved the Prabang Buddha, sacred religious statue and symbol of royalty, from Luang Prabang to Vientiane.
Sent his brother to take the northern city of Loung Prabang from his cousin Prince Kitsarath, grandson of King Suliyavongsa who refused to recognize his authority. Prince Kitsarath ask for assistance from the Siamese King and was granted independence from Lanxang, which divided into rival kingdoms at Vientiane and Luang Prabang during his reign.
while the Cousin of Prince Kitsarath another grandson of Suliyavongsa, Prince Nokasat Song saw the opportunity to break away from Lanxang to the South, also granted independence from Siam to form the kingdom of Champasak, which further divided the Lao Kingdom.
King Sethathirat II had issue three son's and one daughter. 1) Prince (Sadet Chao Fa Anga) Lankaya [Ong-Long], who succeeded as H.M. Samdach Brhat Chao Dharma Adi Varman Maha Sri Ungalankaya Chandrapuri Sri Sadhana Kanayudha, King of Lang-Xang Vientiane. 2) Prince (Sadet Chao Fa Anga) Bunya [Ong-Bun], who succeeded as H.M. Samdach Brhat Chao Maha Sri Bunyasena Jaya Setha Adiraja Chandrapuri Sri Sadhana Kanayudha [Bunsan], King of Lang-Xang Vientiane. 3) Prince (Sadet Chao Fa Jaya) Guangnaya [Khuang-Na]. Appointed as Viceroy with the title of Samdach Brhat Chao Maha Uparaja 1730. 1) A daughter. m. 1699, Phra Chao Sarasak, Upayuvaraja of Ayudhya, son of Phra Phetraja, King of Ayudhya 1684-1698.