The first evidence for the opening of the sea route between India and China comes from the report of a Chinese traveller, Fa Hsien, in 413 AD that he had taken a ship from Sri Lanka directly to China. The beginning of the T'ang dynasty in 618 AD brought renewed stability to China and greatly stimulated the trade and traffic on the India-China sea route through the Indo-Malayan archipelago. For the kingdoms along the Sunda and Malacca Straits, their goal was no longer merely to participate in the China-India trade but to control it as it passed by their territories.
For more than 600 years, the Buddhist kingdom of Sri Vijaya was the strongest of the Straits kingdoms. Sri Vijaya was located at Palembang in southern Sumatra facing out on the Sunda Straits. The kingdom is first recorded in 650 AD as having conquered the west Java kingdom of Taruma. A passing Chinese monk in 671, I-Tsing, comments favourably on Sri Vijaya as a fine centre of Buddhist learning. The kingdom was in regular communication and exchange with Nalanda; the centre of Buddhist scholarship in the Ganges delta of northern India.
By 686, Sri Vijaya had asserted its hegemony over the Sunda Straits and the adjacent Javanese kingdoms. A century later, in 775, it had similarly dominated the Straits of Malacca and commanded tribute from all the kingdoms along its shores. Attaining monopoly control over the trade through the Straits and then keeping it demands a special ruthlessness in suppressing rivals and discouraging interlopers. Sri Vijaya was equal to the task.