Kingdom of Vientiane
Following Fa Ngum's death, struggles with Siamese and Burmese states in which his successors became embroiled, sapped the strength of the army and led to the decline and eventual splitting up of Lan Xang. In 1778 the capital of the Kingdom of Vientiane was attacked and destroyed for the first time by a Siamese army. By the 1820s, Laos had reestablished sovereignty over its own borders, enough that the king of Vientiane launched a disastrous military expedition against Siam in 1826 . Laotian forces were overwhelmed by the superior firepower and strategy of the Siamese army, which attacked and destroyed Vientiane for a second time in 1828.