Steele featured on the Ramkhamhaeng Monument. Much of Sukhothai’s success as a new nation is credited to King Ramkhamhaeng the Great. Ramkhamhaeng was born in 1239 and died in 1317 and ruled from 1277 to 1317, during Sukhothai's most prosperous era. He is credited with the establishment of Theravada Buddhism as the religion of the kingdom, as well as developing the Thai language/alphabet.