The Siamese conquest of Lan Na (1774–1775) was a military conflict between the Konbaung dynasty of Burma (now Myanmar) and the Thonburi Kingdom of Siam (now Thailand).

After about two hundred years of Lan Na kingdom under Burmese rule, the Siamese armies under King Taksin of Thonburi led an expedition to the northern city of Chiang Mai.

[2] Ong Kham, the Lao prince who was of Tai Lue origin, sought political refuge in Chiang Mai where he became a Buddhist monk.

Ong Kham, the Tai Lue prince from Luang Phrabang, declared himself King of Chiang Mai in 1727[2][5] as an independent sovereign.

[4] In the early eighteenth century, the weakening influence of the Burmese Toungoo dynasty allowed Lanna to exert some independence.

[4] However, Lanna fragmented into distinct city-states of Chiang Mai, Lampang, Lamphun, Phrae and Nan, each with its own independent rulers.

King Alaungpaya of the new Burmese Konbaung dynasty rose to power in Burma and conquered the Mon Kingdom of Hanthawaddy in 1757.

In 1762, King Naungdawgyi, son and successor of Alaungpaya, sent his general Abaya Kamani to lead the army of 7,000 men[6] to invade Chiang Mai.

Another pretender took the city of Lampang, prompting Thipchang's son Chaikaew to seek support from the Burmese court of Ava.

King Taksin defeated the last rival regime of Sawangkhaburi in 1770 and gained control of Hua Mueang Nuea or Northern Siam.

[3] Phaya Chaban (Thai: พระยาจ่าบ้าน, personal name Boonma),[1][4] Kawila and other Chiang Mai nobles petitioned to King Hsinbyushin that Thado Mindin had abused his powers.

Phaya Chaban fled Chiang Mai and sought refuge with Nemyo Thihapate the Burmese general at Luang Phrabang.

As Nemyo Thihapate finished his campaigns in Luang Phrabang in 1772, he sent an army to attack the northern Siamese border town of Phichai.

[9][11] In 1774, King Hsinbyushin of Burma ordered Mingyi Kamani Sanda the governor of Martaban to organize armies to invade Siam from the west through the Three Pagodas Pass.

King Taksin of Thonburi decided to renew an expedition to Chiang Mai in 1774 due to the fact that the Burmese of Northern Lanna had harassed several Siamese border towns including Phichai and Sawankhalok.

[4] Thado Mindin reported to the Burmese court that the two Lanna nobles Phaya Chaban and Kawila were suspected to be involved in sedition.

However, Nemyo Thihapate protected Phaya Chaban and Kawila, refusing to let Thado Mindin arrest those two Lanna men.

Phaya Chaban marched his retinue down south to Hot where he massacred all the 70 Burmese and ran to submit himself to Chaophraya Chakri at Thoen.

If the king marched north to Chiang Mai, the Burmese might follow the Mons and invade through the Mae Lamao Pass in the rear.

Taksin decided to leave a handful force to guard the Mae Lamao Pass at Tak and proceeded his army to Lampang in December 1774.

Chaophraya Chakri sent an army of 5,000 men led by Phraya Kamphangphet and Phaya Chaban to march to Chiang Mai through Li in another direction.

King Taksin urged his generals to press on the campaign as they risked being attacked from the rear by the Burmese from Mae Lamao Pass.

The three Chaophrayas - Chakri, Surasi and Phichairacha, divided their forces into thirty-four encampments and laid siege on Chiang Mai in January 1775.

King Taksin moved his royal army from Lampang to Lamphun, where he was informed that more Burmese were coming to Banna from the Mae Lamao Pass to the west.

Chaophraya Phichairacha, who responsible for attacking the northern walls of Chiang Mai, was delayed in establishing his camps and formation.

King Taksin praised Chaophrayas Chakri and Surasi for the victory at Chiang Mai but condemned Phichairacha who allowed the Burmese to break through his formation to escape.

Taksin assigned Chaophraya Chakri with the force of 3,000 men[6] to guard Chiang Mai against possible subsequent Burmese attempts to reclaim the city.

King Taksin had to call the northern armies of Chaophraya Chakri from Chiang Mai to go down south to join the Bangkaeo Campaign in Ratchaburi.

On his coronation day in January 1777,[6] he sent the Burmese army of 15,000 men under Amyauk Wun Nemyo Thihathu and Binnya U the Mon general to attack Chiang Mai.

Phraya Wichienprakarn was left with only few thousand men[4] to defend Chiang Mai so he decided to evacuate the city and moved south to Tak.