Tilokkarat, who ruled from 1441 to 1487, was one of the most influential leaders of the Lan Na kingdom. He ascended the throne in 1441 after overthrowing his father, Sam Fang Kaen. This power transition wasn't smooth; Tilokkarat's brother, Thau Choi, rebelled against him, seeking assistance from the Ayutthaya kingdom. However, Ayutthaya's intervention in 1442 was unsuccessful, and Thau Choi's rebellion was quelled. Expanding his domain, Tilokkarat later annexed the neighboring Kingdom of Payao in 1456.

Relations between Lan Na and the burgeoning Ayutthaya kingdom were tense, especially after Ayutthaya supported Thau Choi's uprising. The tension was exacerbated in 1451 when Yutthitthira, a disgruntled royal from Sukhothai, allied himself with Tilokkarat and persuaded him to challenge Trailokanat of Ayutthaya. This led to the Ayutthaya-Lan Na War, primarily focused on the Upper Chao Phraya valley, previously the Sukhothai Kingdom. Over the years, the war saw various territorial shifts, including the governor of Chaliang's submission to Tilokkarat. However, by 1475, after facing several challenges, Tilokkarat sought a truce.

Apart from his military endeavors, Tilokkarat was a devout supporter of Theravada Buddhism. In 1477, he sponsored a significant Buddhist Council near Chiang Mai to review and compile the Tripitaka, a central religious text. He was also responsible for the construction and restoration of numerous prominent temples. Expanding Lan Na's territories further, Tilokkarat extended his influence westward, incorporating regions like Laihka, Hsipaw, Mong Nai, and Yawnghwe.