[1] As a child, his parents had him study for two years in the school of Pascual Rodriguez, and for four months under Ramon Renaldo, until he was forced to stop to work in the family farm.

[2] In May 1896, del Pilar joined the Katipunan and formed a chapter called Matagumpay (Triumphant), taking the symbolic name Pang-una (lit.

His chapter also adopted a flag, a white triangle with a K at each corner, at the hoist of a red field, in the center of which was a mountain with a rising sun on it.

Del Pilar was present in the Tejeros Convention on March 22, 1897, which marked the split between the Magdiwang and Magdalo factions of the Katipunan.

It was del Pilar (along with Gen. Mariano Noriel) that advised Aguinaldo to change the commutation (banishment) to execution of Andres and Procopio Bonifacio.

Del Pilar was exiled to Guam along with Apolinario Mabini, Artemio Ricarte, and other patriots, referred to as Irreconcilables by the Americans.