Between the pacification of Tonkin in the late 1880s and the Nghe-Tinh Soviet Movement of 1930–31, the Thai Nguyen Rebellion wasthe largest and most destructive anti-colonial uprising to occur inFrench Indochina. On August 31, 1917, an eclectic band of politicalprisoners, common criminals and mutinous prison guards seized theThai Nguyen Penitentiary, the largest penal institution in northernTonkin. From their base within the penitentiary, the rebels stormedthe provincial arsenal and captured a large cache of weapons whichthey used to take control of the town. Anticipating a counterattack,the rebels fortified the perimeter of the town, executed French officials and Vietnamese collaborators and issued a proclamation callingfor a general uprising against the colonial state. Although colonialforces retook the town following five days of intense fighting, mopping-up campaigns in the surrounding countryside stretched on forsix months and led to hundreds of casualties on both sides.