Guerrilla Warfare The term guerrilla (Spanish, “little war”) originated in the early 19th century during the Peninsular war when, after the defeat of Spain’s regular forces, Spanish irregulars and civilians rose up against the French occupying forces. The practice of guerrilla warfare, however, dates from antiquity; for example, the Bible tells of the Israelite conquest of Canaan, led by Joshua, involving harassment and ambush of the enemy. Later Jewish resistance to foreign rule was expressed in the series of fierce guerrilla operations against the Romans in the 1st century AD; led by the Zealot s