Editing Setthathirath (section)

==The Burmese invasions==
{{See also|Burmese–Siamese War (1563–1564)}}
[[File:Phra That Si Song Rak.jpg|thumb|200px|Stupa of [[Phra That Si Song Rak|Wat Phra That Si Song Rak]], Loei, Thailand, competed in 1563 by Setthathirath and King [[Maha Chakkraphat]] to cement the alliance between Lan Xang and Ayutthaya]]
In 1563, a treaty was signed between Lan Xang and Ayutthaya, which was sealed by the betrothal of Princess Thepkasattri (whose mother was Queen [[Suriyothai]] of [[Ayutthaya (city)|Ayutthaya]]). However, King [[Maha Chakkraphat|King Maha Chakkraphat]] instead tried to exchange Princess Kaeo Fa, which was immediately rejected.{{sfnp|Wyatt|2003|p=80}} In the midst of the disagreement, the [[Burmese–Siamese War (1563–1564)|Burmese invaded northern Ayutthaya]] with the assistance of [[Mahathammarachathirat (king of Ayutthaya)|Maha Thammaracha]] the royal viceroy and governor of [[Phitsanulok]]. It was only then in 1564 that King Chakkraphat sent Princess Thepkasattri to Lan Xang along with a massive dowry in an attempt to buy back the broken alliance.{{sfnp|Wyatt|2003|p=81}}

While the procession was en route, Maha Thammaracha ambushed the princess and sent her to his overlords in Burma; she committed suicide shortly thereafter or en route. Facing the threat of a superior Burmese force, King Chakkraphat had lost a potential alliance with Lan Xang, the northern territories of Ayutthaya and his daughter. To prevent further incursions, King Chakkraphat became a vassal of Burma and had to deliver both himself and his son [[Prince Ramesuan]] as hostages to King Bayinnaung leaving another son [[Mahinthrathirat|Prince Mahinthrathirat]] as a vassal in Ayutthaya.{{sfnp|Wyatt|2003|p=81}}

The Burmese then turned north to depose King Mekuti of Lanna, who had failed to support the Burmese invasion of Ayutthaya in 1563.<ref name=geh-167-168>Harvey 1925: 167–168</ref><ref name=my-2-266-268>Maha Yazawin Vol. 2 2006: 266–268</ref> When Chiang Mai fell to the Burmese, a number of refugees fled to Viangchan and stripped of supplies. When the Burmese took Viangchan they were forced into the countryside for supplies, where King Setthathirath had organized [[guerrilla]] attacks and small raids to harass the Burmese troops. Facing disease, malnutrition and demoralizing guerrilla warfare, King Bayinnaung was forced to retreat in 1565 leaving Lan Xang the only remaining independent [[Tai peoples|Tai]] kingdom.{{sfnp|Simms| 1999|p=73–75}}{{sfnp|Stuart-Fox| 1998|p=81–82}}