Theravada Buddhism has prospered in Lan Na during the reign of the religious king Kue Na, who establishes the dhatu of Doi Suthep in 1386.

Kue Na promots the Lankawongse sect and invites monks from Sukhothai to replace the existing Mon Theravada Buddhism that Lan Na had inherited from Haripunchai.

At the ascension, in 1387, of fourteen-year-old Saenmuengma (which means ten thousand cities arrive—to pay tribute) to the throne of the northern Thai mountain kingdom, his uncle, Prince Phrohm, begins plotting to seize the crown.

Failing in this, he calls upon Ayutthaya’s King Borommarchathirat for aid.

The Ayutthayan king, harboring secret ambitions to control Chiang Mai, dispatches an army north.

Sen Muang’s force meets the invaders near the city of Chiang Mai, defeating them at the Battle of Sen Sanuk and compelling their withdrawal from the country.

This is the first armed conflict between the two kingdoms.