Here's a look into the Christianization of the Igorots as presented during the 50th Anniversary of the Holy Rosary High School entitled: "Kayan Mission: A Brief History".

In 1665, more than a hundred years after the discovery of the Philippines by the Spaniards, a Spanish Military Expedition under the command of Admiral Pedro Duran de Monforte reached Kayan (Cayan in old records) through thick and thorns in search for gold which was believed to exist along the mountains of now named Lepanto. With them were three Agustinian friars, one of whom was Father Pedro Diaz, who settled in Kayan, hence the origin of "the Old Mission of Kayan", also known as the Mission of the Archangel Michael.

[Ms. Philian Louis C. Weygan discusses the similarities between Igorot religion and Japanese Culture article in her column "Sangal di Kultura". Ms. Weygan is the executive director of the Upland Development Institute and the Association of Young Igorot Professionals.]

Indigenous peoples and most Asians consider their religion as part of an intricate web with the other aspects of culture (sangal di kultura) that dictate their way of life. This is in contrast to most Western worldview of compartmentalized religion.