After the death of King Udayadityavarman I. in the year 1000 there was no legitimate heir to the throne, which led to the throne was disputed between Jayaviravarman and Suryavarman. Both claimed to be king of the Khmer. Suryavarman belonged to Buddhism and to be of Malay descent. After about nine years of turmoil throne itself Suryvarman I was able to prevail.
The reign of Suryavarman lasted about forty years, and most of the time he had to fight for his rule. He is known as the king of righteous laws. He had four thousand officers compete in the royal palace and swear an oath of allegiance to the king. Although Suryavarman was a Buddhist, he also allowed the Hinduism in Angkor.
Suryavarman palace was near Angkor Thom. He was the first leader of the Khmer, who built his palace at a city wall. In 1022, he expanded the territory of Angkor up to Lopburi in Thailand of today and into the present-day Laos.
Suryavarman had numerous buildings built, including Prasat Preah Vihear in Dangrek - mountains and Phimeanakas. He also started the construction of the second water reservoir in Angkor. This so-called West Baray was applied than 2.1 kilometers by 8 kilometers large lake and is now the largest remaining water reservoir of the Khmer Empire.
Suryavarman I died in 1050. Was succeeded by his son Udayadityavarman II to the throne.