Srivijaya was one of the greatest empires in the Malay Archipelago. It lasted for possibly about 1,000 years and had interacted with so many proud kingdoms that existed during its time. The Chinese civilization was the source of Srivijaya richness through a tributary system, which gifts were exchanged between the courts of the two emperors. The exchange was not exactly free trade but it was trade nonetheless. In the east, there was the Chola of which the great Rajaraja was king. In most cases, the two outsiders exerted stronger influence on Srivijaya culturally, economically and politically though from time to time, Srivijaya exported culture to China due to it being the center of Buddhism outside of India. Apart from that, Srivijaya left a mark on one of the great kingdoms of Southeast Asia — the Khmer Empire.
Some time in the 8th and the 9th century, for reasons not quite clear, Srivijaya conducted raids against a small area located in modern day Cambodia. That place, somewhere along the Mekong, is suspected to be Indrapura.
A 10th century Arab historian, Abu Zaid Hasan wrote that a Khmer king desired to see the head of a Srivijayan emperor. The news somehow traveled from Indochina all the way to the Srivijayan emperor, Samaratunga. Samaratunga was one of, probably at least, 40 emperors of Srivijaya. One point of interest: he and the Sailendras completed the Borobudur in 825. The Borobudur is of course one of the most famous monuments in the world.
According to the Arab historian further, Samaratunga became enraged and led a force to Cambodia to swiftly took the head of the Khmer king. He returned to Srivijaya soon after and Cambodia was leaderless. A Cambodian noble raised within the Srivijayan realm of Java by the name of Jayavarman was sent to Indrapura as a governor to maintain order. Today, we know that Jayavarman as Jayavarman II.
Srivijaya did not control the banks of Mekong for too long though. The governor installed by Samaratunga declared sovereignty and established the Khmer Empire, famous for its great Angkorian period. The empire prospered up to the 15th century when a new power, the Thai civilization, rose up to take their place in history. About 300 to 400 years earlier, it was the that Thai continually absorbed the Srivijayan cities of Chaiya, Ligor, Kedah and eventually, the rest of the lower Malay Peninsula.
During the same time, the sun was setting on Srivijaya, making way for new powers to be born to culturally enrich Southeast Asia.