A cikin 1571, Masarautar Ayutthaya da Lan Na sun kasance 'yan Burma .Bayan sau biyu yana kare Lan Xang daga mamayewar Burmese, Sarki Setthathirath ya koma kudu don gudanar da yakin da Daular Khmer .Cin nasara da Khmer zai ƙarfafa Lan Xang sosai, yana ba shi damar shiga teku mai mahimmanci, damar kasuwanci, kuma mafi mahimmanci, bindigogin Turai waɗanda ake amfani da su tun farkon shekarun 1500.Tarihi na Khmer ya rubuta cewa sojojin Lan Xang sun mamaye a 1571 da 1572, a lokacin mamayewa na biyu Sarki Barom Reacha I a cikin giwaye.Dole ne Khmer ya taru kuma Lan Xang ya ja da baya, Setthathirath ya ɓace kusa da Attapeu.Burma da Lao Tarihi sun rubuta kawai zato cewa ya mutu a yaƙi.^[40]Janar Setthathirath Sen Soulintha ya koma Vientiane tare da ragowar balaguron Lan Xang.Ya fada cikin tuhuma nan da nan, kuma yakin basasa ya barke a Vientiane yayin da rikici ya gudana.A 1573, ya fito a matsayin sarki regent amma ya rasa goyon baya.Bayan jin rahotannin tashin hankalin, Bayinnaung ya aika da jakadu suna neman Lan Xang ya mika wuya cikin gaggawa.Sen Soulintha ya sa aka kashe jakadun.^[41]Bayinnaung ya mamaye Vientiane a cikin 1574, Sen Soulintha ya ba da umarnin a kwashe birnin amma ya rasa goyon bayan mutane da sojoji.Vientiane ya fadi ga Burma.An aika Sen Soulintha a matsayin fursuna zuwa Burma tare da magajin Setthathirath Prince Nokeo Koumane.^[42] Wani vassal Burma, Chao Tha Heua, an bar shi don gudanar da Vientiane, amma zai yi mulki shekaru hudu kawai.An kafa Daular Taungoo ta farko (1510-99) amma ta fuskanci tawaye na cikin gida.A shekara ta 1580 Sen Soulintha ya dawo a matsayin ɗan ƙasar Burma, kuma a shekara ta 1581 Bayinnaung ya mutu tare da ɗansa Sarki Nanda Bayin da ke iko da Daular Toungoo.Daga 1583 zuwa 1591 an yi yakin basasa a Lan Xang.^[43]