From WikiPilipinas: The Hip 'n Free Philippine Encyclopedia
Reduccion System was a resettlement policy employed by the Spaniards which was designed for a convenient administration of the colonies. The Spanish authorities enticed the natives to live near the churches, or within hearing distance of church bells (in Spanish: bajo de la campana). Looking back, Christianity was introduced based on the Filipino natives' familiarity in animist belief. The faces of the anito and diwata were changed to that of the great saints. The horrifying creatures, such as aswang and kapre were transformed to devils in Christian faith. Fiestas and festivals, then as native ritual feasting, were celebrated in honor of the town's patron saint. Some natives remained firm, not obeying this Spanish imposition. Such were called vagamundos - people living from one town to another so that they'll be "excused" from paying tribute.