The government, meanwhile, pressed ahead with plans for Muslim autonomy without the MNLF's cooperation. Article 10 of the 1987 constitution mandates that the new congress establish an Autonomous Region in Muslim Mindanao. In the November 1989 plebiscite, only two Mindanao provinces--Maguindanao and Lanao del Sur--and two in the Sulu Archipelago--Sulu and Tawitawi-- opted to accept the government's autonomy measure. The fragmented four-province Autonomous Region for Muslim Mindanao, with its own governor and unicameral legislature, was officially inaugurated on November 6, 1990.