Around the year 1238 Pho Khun Sri Indraditya became the first King of Sukhothai, when he drove out the Khmer and founded the Sukhothai Kingdom. King Ramkamhaeng created in 1283 the first Thai alphabet so that it was a symbol of the nation's independence.
The Kingdom reached the peak of its power during the reign of King Ramkhamhaeng the Great who expanded the empire during his rule from 1278 until 1298.