 The Philippines' early states must have become the tributary states of the powerful Buddhist Srivijaya empire that controlled the trade and its sea routes from the 6th century to the 13th century in Southeast Asia.The states's trade contacts with the empire long before or in the 9th century may have served as the conduit for introducing Vajrayana Buddhism to the islands.Both Srivijaya empire in Sumatra and Majapahit empire in Java were unknown in Western history until 1918 when George Coedes of the Ecole Francaise d’Extreme Orient postulated their existence because they had been mentioned in the records of the Chinese Tang and Sung imperial dynasties.