King Ashoka sent missionaries to the land of Suwannaphum, which has sometimes been identified as the mainland southeast Asian region of Mon (now a stat in Myanma, the stat of Mon) and Khmer (now Cambodia) people.
"Unconfirmed Singhalese sources state that Buddhism was introduced to Suvannaphum, or the 'Golden Peninsula', as mainland Southeast Asia was once referred to, in the 3rd century B.C. under the reign of King Ashoka, the great Buddhist ruler.