Lan Chang Province was named after the ancient
Lan Xang kingdom, to which the area had once belonged. Its name means a 'Million
Elephants'. In 1904,
Siam ceded the Laotian inhabited area of the Luang Prabang Range to colonial French Indochina. In August 1940, after a series of border clashes, the
Axis-leaning government of Thailand attacked French military posts on the eastern banks of the
Mekong between
Vientiane and
Champassak Province. Both Thailand and the French colonial government would declare war. The more modern Thai Army won many victories on land, but the Royal Thai Navy was caught by a larger French fleet and suffered a humiliating defeat. The
Japanese government intervened to mediate a ceasefire. In the ensuing talks in 1941, the French colonial government was forced to cede western Champassak Province and all of Xaignabouli of Laos and
Battambang Province of
Cambodia to the Thais. Zaignabouli was renamed the province of Lan Chang. The Thai administration was not very active in the province during that time and the largely rural districts were pretty much left to themselves until they were reincorporated into Laos. At the end of World War II
France threatened to block Thai entry into the
United Nations unless it returned the provinces to their colonial empire. The Thai government, now under the control of members of the underground who had opposed the Japanese, was anxious to show its repudiation of the previous military government. It willingly signed the Washington Accord, surrendering all war time territorial gains. Lan Chang Province was returned to Laos in 1946 and resumed its pre-war name. ==Administrative divisions==