They unveiled the historical marker at the Mindanao Garden of Peace in the island which tells the story of the Jabidah Massacre.
The government, in 1968, secretly recruited young moros to create the Jabidah special commando unit. The plan was to takeover the Sabah territory from Malaysia.
Coming from impoverished towns in Muslim Mindanao, the young moros were lured with the promise of a monthly stipend and a better life.
When the plan went south, the government conspired to cover it up and killed the young Moros in Corregidor.
But one survived and exposed the massacre. He died in a vehicular accident in 2011.
You can read more about the massacre here.
To this day, some still say the Jabidah Massacre is a myth. But in 2013, the government finally acknowledged the gruesome incident when President Aquino spoke at the 45th commemoration.
Whether it really happened or not, journalists and historians still point to the massacre as what sparked the Muslim rebellion in Mindanao.