Fermán Cienfuegos

José Eduardo Sancho Castañeda, better known by hius nom de guerre Fermán Cienfuegos (born 6 March 1947) was the leader of the Salvadoran organization Fuerzas Armadas de la Resistencia Nacional (National Resistance Armed Forces in English, part of Resistencia Nacional or RN). He was born in San José, Costa Rica.

The RN was founded in 1975 as a split from the Ejército Revolucionario del Pueblo (ERP - People's Revolutionary Army) after an internal struggle within the ERP resulted in the assassination of a group of ERP leaders including famed Salvadoran poet Roque Dalton who advocated that the ERP should not have such a largely militarist focus and should do more organizing among the masses.

In 1980, the RN was one of the five revolutionary Marxist organizations that formed the Farabundo Martí National Liberation Front that fought an armed struggle against the Salvadoran government. As the leader of the RN, Cienfuegos was one of the signatories of the 1992 Salvadoran peace accords.