Spanish colonialism had, from its formal inception in 1565 with the arrival of Miguel López de Legazpi, as its principal raison d'ętre the conversion of the inhabitants to Christianity. When Legazpi embarked on his conversion efforts, most Filipinos were still practicing a form of polytheism, although some as far north as Manila had converted to Islam. For the majority, religion still consisted of sacrifices and incantations to spirits believed to be inhabiting field and sky, home and garden, and other dwelling places both human and natural. Malevolent spirits could bring harm in the form of illness or accident, whereas benevolent spirits, such as those of one's ancestors, could bring prosperity in the form of good weather and bountiful crops. Shamans were called upon to communicate with these spirits on behalf of village and family, and propitiation ceremonies were a common part of village life and ritual. Such beliefs continued to influence the religious practices of many upland tribal groups in the modern period.

The religious system that conquistadors and priests imported in the sixteenth and seventeenth centuries was superimposed on this polytheistic base. Filipinos who converted to Catholicism did not shed their earlier beliefs but superimposed the new on the old. Saints took primacy over spirits, the Mass over propitiation ceremonies, and priests over shamans. This mixing of different religious beliefs and practices marked Philippine Catholicism from the start.

From its inception, Catholicism was deeply influenced by the prejudices, strategies, and policies of the Catholic religious orders. Known collectively as friars, the orders of the Augustinians, Dominicans, Franciscans, and others, and the Jesuits turned out to be just about the only Caucasians willing to dedicate their lives to converting and ministering to Spain's subject population in the Philippines. They divided the archipelago into distinct territories, learned the vernaculars appropriate to each region, and put down roots in the rural Philippines where they quickly became founts of wisdom for uneducated and unsophisticated local inhabitants (see The Friarocracy , ch. 1). Because most secular colonial officials had no intention of living so far from home any longer than it took to turn a handsome profit, friars took on the roles of the crown's representatives and interpreters of government policies in the countryside.

The close relationship between church and state proved to be a liability when the Philippines was swept by nationalistic revolt in the late nineteenth century and Filipino priests seized churches and proclaimed the Independent Philippine Church (Iglesia Filipina Independiente). After the American occupation, Protestant missionaries came and established churches and helped to spread American culture.

Data as of June 1991