The northern state of Lanna, centered in Chiang Mai, is another Thai state that coexists with Sukhothai and had emerged in the same period.

King Phya Mangrai is its founder.

Lanna has evidently become closely allied with Sukhothai.

Sukhothai is finally subdued after the Ayutthaya kingdom has emerged and expanded its influence from the Chao Phraya valley,

Fierce battles between Lanna and Ayutthaya also constantly take place and Chiang Mai is eventually subjugated also, becoming Ayutthaya's 'vassal'.