Manila: Malaca±ang Palace has declared September 11 as a special non-working day in the Cordillera Administrative Region, commemorating the 40th anniversary of the Mount Data Sipat Agreement.

According to Philippines News Agency, Proclamation 1389, signed by Executive Secretary Ralph Recto, was made available to the public through the Official Gazette on August 12. The holiday commemorates the peace pact signed on September 13, 1986, between the national government, led by President Corazon Aquino, and the Cordillera People's Liberation Army, represented by leader and "rebel priest" Conrado Balweg.

The term "Sipat" refers to an indigenous system used for settling disputes, where parties exchange peace tokens as a sign of their commitment to fulfilling the terms agreed upon. In this historic event at Mt. Data, Bauko, Mountain Province, the government received a spear and a shield, while Balweg was presented with a rosary, a bolo, and a head ax.

The Sipat Agreement marked the first successful peace accord entered into by the national government during Aquino's administration. It subsequently led to the issuance of Executive Order 220 on July 15, 1987, which established the Cordillera Administrative Region.