Suryavarman I

Suryavarman I (; posthumously Nirvanapada) was king of the Khmer Empire from 1002 to 1050. Suryavarman usurped King Udayadityavarman I, defeating his armies in approximately 1002. After a protracted war with Udayadityavarman's would-be successor, Jayavirahvarman, Suryavarman I claimed the throne in 1010. His own inscriptions do not derive his title from his predecessors. K.275 states that he was born into the family of Indravarman I, and K.380 and K.660 that his queen Vīralakṣmī belonged to the line of Harṣavarman I and Īśānavarman II, while K.136 and K.161 concede that he had no claim by descent from the kings who immediately preceded him and took the kingdom by battle. Proposals that he originated instead in a ruling family in what is now Thailand or on the Malay Peninsula have been described by Michael Vickery as ingenious speculation for which convincing proof is lacking. Suryavarman was a Mahayana Buddhist It seems that the Khmer king Suryavarman I requested aid from the powerful Chola Emperor Rajendra Chola against the Tambralinga kingdom. After learning of Suryavarman's alliance with Rajendra Chola I, the Tambralinga kingdom requested aid from the Srivijaya king Sangrama Vijayatungavarman. That eventually led to the Chola Empire coming into conflict with the Srivijiya Empire. The war ended with a victory for the Chola dynasty and the Khmer Empire, major losses for the Sri Vijaya Empire and the Tambralinga kingdom.

His reign lasted some 40 years, and he spent much of that time defending it. Known as the "King of the Just Laws," he consolidated his political power by inviting some 4000 local officials to the royal palace and swear an oath of allegiance to him. The oath survives in six inscriptions cut in 1011, at the close of the nine-year war of succession. The major constructions by the king were Preah Vihear, on Dangrek Mountain, and completion of the Phimeanakas and Ta Keo. It held more than 123 million liters of water. That is the largest Khmer reservoir to survive. There is some indication that Suryavarman sent a gift to Rajendra Chola I, the Chola Emperor.

During his reign, 47 cities (known as 47 pura) were under the control of Khmer Empire.

Suryavarman died in 1050 and was given the posthumous title Nirvanapada ("the king who has gone to nirvana"), a nod to his Buddhist beliefs. The epigraphic record as summarised by U-tain Wongsathit and his co-authors places the death in 1049 and gives the posthumous name as Paramanirvāṇapada; the same summary names a second queen, Nṛpatīndralakṣmī, and a son, Prince Vīravardhana, from the inscription K.989.