In 1859, the Escuela Municipal bore the coat of arms of the City of Manila, which were granted by King Philip II of Spain in 1596. When the title "Ateneo" was added to the school's name in 1865, the seal incorporated the Jesuit monogram "IHS" and Marian symbols. At its golden jubilee in 1909, clearer Marian symbols were added along with the current motto, "Lux in Domino". In 1929 for Ateneo’s diamond jubilee Fr. Rector Richard O’Brien, S.J., introduced the present seal which replaces the arms of Manila with mostly Jesuit and Ignatian symbols.