In the First Invasion in 1850, the Siamese court had ordered the Lanna Lord of Chiang Mai to organize the offensives against Kengtung.

Kengtung was founded as a city by King Mangrai of Ngoenyang in 1253[1] and later became part of the Tai Yuan Kingdom of Lanna, which encompasses modern Northern Thailand.

The Lanna Lords adopted the policy of “Picking vegetables into baskets, putting men in towns”[3] to wage wars to seek manpower.

The Northern Tai states of Kengtung and Chiang Hung, known collectively in Thai sources as "Lü-Khün", were the main victims of forced resettlement policy to repopulate the Lanna region, which had been ravaged by prolonged warfare.

In 1802, Phraya Kawila of Chiang Mai sent his younger brother Phraya Uparaj Thammalangka to capture Mong Hsat and Kengtung, forcibly deporting thousands of Khun people from Kengtung and Mong Hsat to resettle in Chiang Mai.

Maha Khanan, younger brother of Sao Kawng Tai, established himself at Mong Yawng as an independent ruler.

King Bodawpaya was angered at Mahanavi's defiance and enfeoffed Mahavang to replace his nephew as the ruler of Chiang Hung.

Lady Pinkaew, wife of Mahavang and mother of Suvanna and Amaravuth, bribed[7] the Burmese Sitke to retreat.

Seven days after, Lord Mahachai of Mengpeng who was a supporter of Suvanna led troops to recapture Chiang Hung.

Four years later in 1842, the Qing authorities in Yunnan encouraged Mahachai of Mengpeng to successfully retake Chiang Hung and restore Suvanna to the throne for the second time.

King Sukkhasoem of Luang Phrabang then sent the Tai Lue royals; Amaravuth, Lady Pinkaew and Mahachai to Bangkok.

[7] King Rama III sent troops to assist Tsau Suvanna of Chiang Hung against Nokham to uphold the chakravatin ideology of universal ruler, which signified the honor and power of the Siamese kingdom in the region.

King Rama III ordered Phraya Mahavong the Ruler of Chiang Mai to arrange Lanna armies into Kengtung.

The Lanna side suffered from manpower shortage as the army of Uparaj Phimphisan did not coalesce with them at Kengtung as planned.

Phraya Mahavong of Chiang Mai issued a letter of apology[7] to King Rama III at Bangkok, beseeching him for Bangkokian assisting troops and additional cooperation from Nan.

Amaravuth, Lady Pinkaew and Mahachai, the Tai Lue royals, who had been staying in Bangkok for about three years, took the permission of King Mongkut to return to the north.

On this occasion Bangkok was involved directly by sending its troops in the campaigns; The two armies planned to converge at Chiang Saen before proceeding to Mong Hpayak and then to Kengtung.

The prince ordered Chao Phraya Yommaraj Nuch to be his vanguard, with the joint Bangkok-Chiang Mai army of total 5,042 men, who left first from Chiang Saen to Mong Hpayak on February 24.

Another issue was that Kengtung was a hill fort and the Siamese occupied relative lowland positions, complicating the abilities of their canons to inflict damages onto the higher elevations.

Yommarach Nuch ordered Lanna regiment to assault on Kengtung city walls but were repelled by Maha Khanan.

Prince Vongsathirat Sanid took the rainy season break at Nan and Chao Phraya Yommaraj Nuch at Tak.

[8] Sri Suriyawongse and Yommaraj Nuch traveled to meet Prince Vongsathirat Sanid at Uttaradit, where they planned for the incoming second expedition to Kengtung, in November 1853.

As he ran out of food supplies and gunpowder, Prince Vongsathirat Sanid finally decided to retreat from Kengtung on March 18 to Nan.

Chao Phraya Mongkol Vorayot of Nan then acted as rearguard to defend the Siamese armies against the Burmese counter-attacks.

Yommaraj Nuch, who had marched halfway to Kengtung, retreated to Chiang Mai upon learning of the prince's defeat.

King Mongkut ordered Prince Vongsathirat Sanid and Chao Phraya Yommaraj Nuch to pull the troops back to Bangkok in 1854.

A Qing delegated arrived in Luang Phrabang requesting for the return of Amaravuth, Lady Pinkaew and Mahachai to Chiang Hung.

Maha Khanan held the position of saopha of Kengtung for four decades from Burmese recognition in 1813 to the times of Siamese invasions in early 1850s.

Even though the British had indirectly recognized Salween River as Burma-Lanna border in the Anglo-Siamese Chiangmai Treaties of 1874 and 1883 by saying that;[11] His Majesty the King of Siam will cause the Prince of Chiengmai to establish and maintain guard stations, under proper officers, on the Siamese bank of the Salween River, which forms the boundary of Chiengmai belonging to Siam...meaning that the trans-Salween states to the east of Salween on the 'Siamese bank' belonged to Lanna-Siam by this definition, however, they saw that Kengtung should come under British rule because Kengtung had been a long-time vassal of Burma and Lanna-Siam had not held any authorities over Kengtung.

[9] Kawn Kham Hpu the ruler of Kengtung eventually agreed to accept British rule and to join the durbar of Shan States.