The Feast of Our Lady of Guadalupe, celebrated on December 12, marks the anniversary of a significant event in Catholic tradition. In 1531, St. Juan Diego, an indigenous man from Tepeyac near Mexico City, reported an apparition of a woman who identified herself as the Mother of the True God. She instructed him to ask the local bishop to build a church at the site. As proof for the bishop, she left her image imprinted on Juan Diego’s tilma, a cloak made from cactus fiber.

According to tradition, “the tilma should have deteriorated within 20 years but shows no sign of decay after nearly 500 years. To this day it defies all scientific explanations of its origin.” The appearance of this image is credited with leading many native people in Mexico to accept Christianity and has become deeply woven into Mexican history.

Juan Diego was among the first native people baptized into Christianity in the region. The story recounts that while he was passing Tepeyac Hill one December day, he heard a voice and saw a woman who spoke his language and requested that a chapel be built there. After initial skepticism from the bishop, Juan Diego returned to Tepeyac where he found roses blooming despite winter conditions—roses he gathered in his cloak at Mary’s direction.

When Juan Diego presented these roses to the bishop, “a miraculous image of Mary was on the tilma.” The name “Guadalupe” used by Mary matched that of a well-known shrine in Spain, surprising Spanish observers at the time. Artistic influences from Spain, Italy, and France are evident in the image according to experts. The Spaniards recognized Christian symbols such as Mary standing on a crescent moon and wearing blue garments.

A basilica was constructed at Tepeyac Hill’s base following these events; it was later replaced by a new basilica consecrated in 1976.

Scientific inquiry has explored several mysteries surrounding the tilma. Astronomers have noted that star patterns on Mary’s robe match how stars appeared over Mexico City on December 12, 1531. Some flowers depicted correspond geographically with Mexican volcanoes—a feat considered unlikely for artists then.

Magnified examinations have revealed what appear to be tiny figures reflected in Mary’s eyes—possibly representing witnesses present during Juan Diego’s meeting with Bishop Juan de Zummaraga—and conforming to optical laws not understood until centuries later.

Analyses indicate there is no preparatory sketch or protective varnish on the image; microscopic study found no brush strokes. Observers report that “the image seems to increase in size and change colors due to an unknown property of the surface and substance.” Kodak of Mexico described it as feeling like a modern photograph created long before photography existed.

The tilma itself remains largely intact despite being made from fragile agave fibers and having been exposed for over a century without protection amid environmental hazards or physical contact by thousands. Attempts at damage—including exposure to nitric acid in 1785 and an explosion caused by dynamite in 1921—did not harm the image.

Each year about ten million people visit Our Lady of Guadalupe’s Basilica in Mexico City, making it one of Christianity's most visited sites after St. Peter’s Basilica at Vatican City.

In 1999 during his third visit to this sanctuary, Pope John Paul II declared December 12 as a liturgical holy day across Latin America: “During the same visit,” he also “entrusted the cause of life to her loving protection and placed under her motherly care the innocent lives of children, especially those who are in danger of not being born.”

“Feast of Our Lady of Guadalupe celebrated Dec. 12

By JONAH McKEOWN 

Catholic News Agency

In 1531 a ‘Lady from Heaven’ appeared to St. Juan Diego, a poor Indian from Tepeyac...As a sign for the bishop, she left an image...on his tilma...To this day it defies all scientific explanations...”

“It wasn’t until ...Our Lady ...appeared that ...native people began ...to accept Christianity...Today ...the image forms an ...part ...of Mexico ...and facilitated ...evangelization...”

“In ...1530s,...Juan Diego was ...in his 40s...member ...first native tribes baptized....he heard …voice calling…he saw …woman…spoke…native tongue…and told him…wanted chapel built…”

“Juan Diego delivered message …bishop,…didn’t believe him…Diego returned …hill,…Mary’s direction,…found roses growing…even though…it was winter.…He gathered them into his cloak…”

“When he unfurled…the cloak…to show…the roses,…miraculous image…Mary was on…the tilma.”

“Mary herself used…the name ‘Guadalupe.’ Guadalupe was…the name…shrine in Spain,…which surprised…the Spaniards.…Spanish,…Italian,…French artistic influences can be detected.…Spaniards perceived…the image as Christian icon,...such as imagery…moon at Mary’s feet…and blue dress.”

“A basilica was built …base …hill,...eventually began crumble.…new basilica consecrated …1976.”

“The mysteries surrounding…the tilma are innumerable,...many have been tested or brought …forefront thanks …scientific inquiry.”

“For example,...astronomers have determined arrangement stars on Guadalupe image corresponds how stars would have appeared Dec.…12,…1531.…some flowers correspond locations volcanoes…Mexico…”

“Under great magnification,...shadowy figures discerned Mary’s eyes,...scale not possible human painter....analyses suggested bearded man…and even several other figures...(believed images Juan Diego,Bishop Juan de Zummaraga,...Juan Gonzales-the interpreter...)...,tiny images conforming optical laws not known until nineteenth century—such reflection patterns real human eyes.”

“There is no under sketch,no sizing,and no protective over-varnish....Microscopic examination revealed there were no brush strokes....image seems increase size change colors due unknown property surface substance which made.According Kodak Mexico,image smooth feels like modern-day photograph — produced three hundred years before invention photography.Image consistently defied exact reproduction,whether brush camera.”

“Another baffling mystery is tilma's longevity.Cloak shows almost no signs aging despite fragility agave thread fact kept unprotected smoky,salty environment over hundred years seen touched thousands people.Science cannot explain tilma,to this day.”

“Other more miraculous occurrences borne witness cloak's resilience.At one point,in seventeen eighty-five when frame cleaned,nitric acid spilled accident,left no permanent stains.A man once tried nineteen twenty-one blow up detonating dynamite church,but despite church practically crumbling around,image unharmed.”

“Each year estimated ten million people visit Basilica,making Mexico City home most popular Marian shrine world,and most visited Catholic church world after St.Peter's Basilica Vatican."

"The Feast Our Lady Guadalupe celebrated Dec.twelve.In nineteen ninety-nine St.Pope John Paul II,in homily given during Solemn Mass Basilica Our Lady Guadalupe third visit sanctuary declared date Dec.twelve Liturgical Holy Day whole continent.During same visit,Pope John Paul II entrusted cause life loving protection placed under motherly care innocent lives children especially those danger not being born."

“Our Lady of Guadalupe pray for us!”