The Christians in ARMM (Autonomous Region of Muslim Mindanao) are primarily descendants of immigrants from Luzon. The massive immigration was brought about by a very successful pacification campaign by a hitherto unknown U.S. Army Captain in 1903.
One Captain John J. Pershing.
In Zamboanga City, in the heart of Muslim Mindanao, is the hub of free speech and the like. It’s called General Pershing Square, to commemorate his success against the hostile Datus (or Rajahs).