During World War II, Camarines Sur came under Japanese occupation in late December 1941, following the capture of Naga City on December 18, a few days after the Japanese invasion of Legaspi. Guerrilla units were organized by Wenceslao Q. Vinzons that waged underground operations against the Japanese troops stationed in Camarines Sur. After the capture of Vinzons on July 8, 1942, the guerrilla movement was carried on by Lieutenant Francisco Boayes and by the Tangcong Vaca Guerrilla Unit organized by Elias Madrid, Juan Miranda and Leon Aureus. In April 1945, Camarines Sur was finally liberated from the Japanese invaders against the combined Filipino and American troops in 1945.