One of earliest established is a visita (sub-parish) is Pililla in Morong, Rizal, among them is Monte de Tan-ay (now part of the present town of Tanay).

The first church made up of wood and cogon grass as its roof was also established in San Antonio but was eventually burned down by the flaming arrows of marauding Aetas.

Church records state that only a very old image of La Purísima Concepción was saved from the attack, believed to have been left in haste by the retreating Spanish forces.

A popular story recounts how a Franciscan priest, Geronimo de Frías, hid the image of La Purísima inside the jungle nearby.

After the rebels were oppressed, the priests transferred the parish to its present site, formally establishing the town of Tanay in the same year.

By 1773, the construction of the present church began through the initiative of Alonzo de Fentanes and the people of Tanay; it was gradually completed in 1783.