Libyan involvement with Chad can be said to have started in 1968, during the Chadian Civil War, when the insurgent Muslim National Liberation Front of Chad (FROLINAT) extended its guerrilla war against the Christian President François Tombalbaye to the northerly Borkou-Ennedi-Tibesti Prefecture (BET). Libya's king Idris I felt compelled to support the FROLINAT because of long-standing strong links between the two sides of the Chad–Libya border. To preserve relations with Chad's former colonial master and current protector, France, Idris limited himself to granting the rebels sanctuary in Libyan territory and to providing only non-lethal supplies.