Gregorio Agilpay was the principal founder and first Supreme Bishop of the Philippine Independent Church.

Agilpay was born in 1860 and orphaned at an early age. As a boy he worked in the tobacco fields during the Spanish occupation of his homeland and for the rest of his life bore hard feelings toward the Spanish colonialists. He took a degree in law before embarking on theological studies in preparation for the priesthood. He was ordained in 1890, but seems to have been something of a free spirit from the beginning, illustrated by his joining the Freemasons, an affiliation that was forbidden to Catholic priests.