December 12 – Feast of Our Lady of Guadalupe Our Lady of Guadalupe is one of Mary’s most well-known titles. On December 9, 1531, Mary appeared to St. Juan Diego on Tepeyac Hill (now México City). Three days later, on December 12, Juan Diego received a miraculous sign from the Virgin Mary. On this same day, centuries later, we celebrate the Feast of Our Lady of Guadalupe.