The first Khmer kingdom, known as Chenla, adopted the entire culture of Funan for itself. Chenla did not have a strong government, though; it prospered in the 7th century, but in 706 it split into two states, known as "Land Chenla" (Laos) and "Water Chenla" (Cambodia). Land Chenla retained some measure of unity, but constant intrigues for the throne shattered Water Chenla into no less than five smaller states. At the end of the 8th century all of Water Chenla came under the domination of one of Java's Sailendra monarchs.

The incident that caused the Javan conquest also started the Khmers on the road to greatness. It involved a rash young king, whose name we do not know. According to the Arab traveler who provided this account, one day the young king and his prime minister were discussing what to do about Java, the strongest naval power in the region. The king said, "I have one desire I would like to satisfy."
"What is this desire, O King?" his councilor asked.
"I want to see before me on a plate the head of the king of Java."

When the king of Java heard about the Khmer monarch's wish, he led a fleet of a thousand ships up the Mekong River and routed the Khmers defending the capital. Capturing the young king, he said, "You have manifested the desire to see before you my head on a plate. If you had also wished to seize my country or only ravage part of it, I would have done the same thing to Khmer. As you have expressed only the first of these desires, I am going to apply to you the treatment you wished to apply to me, and I will then return to my country without taking anything belonging to the Khmers . . . My victory will serve as a lesson to your successors." He then lopped off the king's head and said to the Khmer prime minister, "Look now for someone who will make a good king after this fool, and put him in the place of the latter."

The new king picked by the prime minister was an excellent choice: Jayavarman II, a distant relative of the late king who had been living in Java to escape the troubles at home. In the course of his long reign (795?-850), he reunited Water Chenla and gave it a new name: Kambujadesa (the origin of the modern names Cambodia and Kampuchea). Despite his success he seems to have been an insecure monarch; he waited until 802 to have his coronation, and before 819 he changed the location of his capital no less than five times. At his last capital, he finally found peace of mind by taking part in a sacred Hindu ceremony that consecrated him as an avatar of the god Shiva and declared him and his kingdom independent of any foreign power, especially Java.

The next important Khmer king was Yasovarman I (889-900). A few miles north of the Tonle Sap he built a new city, called it Yasodharapura, and it became Cambodia's capital for the next five centuries (now it is called Angkor, meaning simply "city"). Most of Angkor's impressive buildings were built later on, but Yasovarman left his mark by constructing an excellent system of canals and reservoirs around the city, using the technology perfected in the age of Funan. Those canals would later be used to feed the large number of laborers used in Angkor's massive building projects. Fortunately for historians, Yasovarman was a great braggart (all Khmer monarchs were), and he left numerous inscriptions boasting of his achievements: "The best of kings . . . unique bundle of splendors", and "In all the sciences and all the sports . . . in dancing, singing, and all the rest, he was as clever as if he had been the first inventor of them." Then came the ultimate boast: "In seeing him, the creator was astonished and seemed to say to himself, `Why did I create a rival for myself in this king?'"

For the 10th and 11th centuries our only source of information is the inscriptions, but it was a time of growth, in size, power, and cultural sophistication. Land Chenla submitted peacefully to Angkor's rule, and it appears that the states in Thailand and Malaya did the same, during the reign of Suryavarman I (1002-50). Suryavarman's son, Udayadityavarman II (1050-66), fought an inconclusive war with the Burmese, who thought the Khmers were getting too close to Thaton. Suryavarman II (1113-50) conquered Champa and campaigned against the Vietnamese; at one point there was a Khmer army in Thanh Hoa, just 80 miles south of Hanoi.

Back at home Suryavarman II built the masterpiece of Khmer civilization. This was a temple to the Hindu god Vishnu so enormous that it was known as Angkor Wat, the "temple city." Using an estimated 455 million cubic yards of stone, this structure was built with five gilded peaks to resemble the mythical Mt. Meru. The entire structure was covered with endless reliefs showing battles, scenes from Hindu epics, and events in everyday Khmer life. The central peak of the structure was also a mausoleum, where Suryavarman's ashes were placed when he died.

The cost of building Angkor Wat and fighting wars abroad drained the treasury. After Suryavarman II was gone the Chams successfully revolted, and in 1177 they sailed up the Mekong River and plundered Angkor itself. Four years of anarchy followed, but remarkably, the best years of Cambodia's history were yet to come. Royal authority was reestablished by Jayavarman VII, a middle-aged prince who had refused the throne when it was first offered to him years before. Jayavarman routed the Chams, drove them back to their home, and was crowned the new king of Angkor. Champa would be a Khmer vassal, not the other way around.

A man of uncommon vigor, Jayavarman spent the rest of his reign (1181-1219, he lived into his 90s) building more monuments than all of the other Khmer kings put together. Chief among these was a remodeled capital city, now called Angkor Thom ("big city"), which was so big and elaborate that only nearby Angkor Wat could rival it. A convert to the Mahayana Buddhist sect, he erected Buddhist shrines and images all over the city (the sculptors used Jayavarman as the model for statues of Buddha), and converted the temples of his Hindu predecessors into Buddhist ones. Around the country he built and maintained 102 hospitals because, as one inscription put it: "He suffered from the sickness of his subjects more than from his own; for it is the public grief that causes the grief of kings, and not their grief."

Some historians believe that Jayavarman's building projects exhausted the kingdom. None of the kings after him built anything important; they lived in luxury, performed their god-king rites, but accomplished little. Champa declared independence as soon as it heard the news of Jayavarman's death, and in the west the Menam River valley was lost to newcomers in the region, the Thais. At the same time Theravada Buddhism became the most popular religion, undermining the god-king cult. In the middle of the 13th century the Khmer king himself converted to Theravada Buddhism, perhaps because of the success of the Thais, who were Theravadists already. In 1296 a Chinese visitor, Zhou Daguan, visited Angkor and took home a glowing report of the city; to him Cambodia was still the strongest state in Southeast Asia. Angkor remained Cambodia's glittering capital until 1431, but long before that time the political initiative passed to its neighbors.