Where is Siam in Song Dynasty now?

Siam [Sai? Sir, Sai? M], Chinese pinyin xiān luó), is the ancient name of Thailand, a Southeast Asian country. Some of its ancestors were ancient China people, who first lived in Yunnan, China, and moved south to Indo-China Peninsula in the Yuan Dynasty to avoid the invasion of Mongols. Siam is culturally influenced by China culture and Indian culture, especially the Buddhist culture from western India, and is still a religious country where all people believe in Buddhism. Siam was renamed "Thailand" on 1949, which means "king of thailand".