Operation Gordian Knot (Operação Nó Górdio) was the largest and most expensive Portuguese military campaign in the Portuguese overseas province of Mozambique, East Africa. The operation was carried out from 1970 to 1971, during the Portuguese Colonial War (1961–1974). The objectives of the campaign were to close down the Mozambique Liberation Front (FRELIMO)'s infiltration routes across the Tanzanian border and to destroy permanent FRELIMO bases inside the liberated zones in Northern Mozambique. Gordian Knot was a seven-month long campaign ultimately employing thirty-five thousand men, and was almost successful since it destroyed most guerrilla camps located inside FRELIMO's liberated zones and captured large numbers of rebels and armaments, forcing FRELIMO to retreat from their bases and