Complex sentence: This policy allowed Christian Filipinos to outnumber both the Moro and Lumad populations by the 1970s, which was a contributing factor in aggravating grievances between the Moro and Filipino Christian settlers as disputes over land increased.
Split into simpler sentences: This policy allowed Christian Filipinos to outnumber both the Moro and Lumad populations by the 1970's. This was a contributing factor in aggravating grievances between the Moro and Filipino Christian settlers as disputes over land increased.