According to one version of the story, a fisherman, upon being asked by the Spaniards about the name of the place, replied "no sapao," meaning he missed catching the school of fish.

Another version suggests that a fisherman responded "sapao," meaning his banca was full of fish.

Eventually, Sapao was reverted into a barrio, part of the municipality of Numancia (now Del Carmen).

It then consisted of barrios Alegria, Baybay, Bailan, Bitaug, Burgos, Cabugsan, Libertad, Rizal, and Sapao.

Poverty incidence of Santa Monica Source: Philippine Statistics Authority[14][15][16][17][18][19][20][21]