Ocampo distinguished himself for being then the only Filipino who studied heraldry abroad and who became a member of the International Institute of Genealogy and Heraldry in Madrid . For the stained glass windows of the Manila Cathedral, he was sent by Archbishop Rufino Santos to Rome to undergo training in stained glass design.
In working on the cathedral window projects, Ocampo entrusted his detailed cardboard sketches of the panels to the Instituto de Arte Liturgica, which undertook the task of transferring them in the form of stained glass. While the various chapels at the cathedral are dedicated to special saints, Ocampo’s designs are mainly along a Marian theme, the Immaculate Conception of Mary being the patroness of the Archdiocese of Manila and the Manila Cathedral. Thus, the general splendor of the ornaments for the entire edifice revolve around the traditional motives of the ineffably rich iconography of the Blessed Virgin Mother of God.
Manila Cathedral’s stained glass windows are not only lovely decorative features of the edifice but truly symbolic media that set religious fervor and a deep understanding of the Faith. They fill the Cathedral with light and beauty, symbolically like Jesus, our Lord and Savior, the Divine Light born of Mary, who has come into the world to fill and heal our souls with His light and love.
A total of 134 stained glass windows are found at the Manila Cathedral, specifically:
The 30 Windows of Central Nave
The 14 windows of the lateral aisle and choir
The 18 windows of the apsis
The 4 windows of the transept
The 2 windows of the presbytery
The 2 windows of the deambulatories
The 12 windows at the end of the transep
The 16 windows of the lantern of the dome
The 33 windows of the chapels
The 3 windows of the façade