At the center of the Our Lady of Guadalupe devotion sits a single object: a cactus fiber cloak that should have disintegrated centuries ago. It has not, and the image on it has drawn scientific and theological scrutiny for nearly five hundred years.
| Topic | Key Fact | Significance |
|---|---|---|
| Material | Maguey (agave) fiber | Typically deteriorates within 20 to 40 years |
| Age | Since 1531 | Nearly five centuries of preservation |
| 1921 Bombing | November 14, 1921 | Bomb destroyed altar steps and bent a crucifix; the tilma was untouched |
| Eye Reflections | First noted 1929, examined by ophthalmologists from 1956 onward | Reported findings consistent with a living eye’s optical behavior |
| Digital Study | 1979, Dr. José Aste Tonsmann | Digital magnification of the eyes at 2,500 times actual size |
A Cloth That Should Not Have Survived
Juan Diego’s tilma was a simple garment, woven from the fiber of the maguey, or agave, plant, the everyday material used for the cloaks of poor and working class men in sixteenth century Mexico. Cloth of this type typically deteriorates within twenty to forty years under normal conditions, especially given Mexico City’s humidity and the tilma’s centuries of exposure to candle smoke, incense, and the touch of countless pilgrims before it was placed under protective glass. Yet the tilma housed at the Basilica of Our Lady of Guadalupe in Mexico City has survived since 1531, through centuries of exposure, an attempted bombing, and generations of scientific examination.
The Image Itself
The image depicts a young woman, hands folded in prayer, standing on a crescent moon and eclipsing the rays of the sun behind her. She wears a rose colored tunic beneath a blue-green mantle covered in gold stars, and a black sash at her waist, a traditional Aztec sign of pregnancy. We cover the full meaning of these details in the next article in this series, but the physical image itself has been the subject of ongoing study since at least the eighteenth century, when the first documented technical examinations were recorded by artists and clergy asked to assess its condition and composition.
The 1921 Bombing
On the morning of November 14, 1921, a man named Luciano Pérez Carpio hid a bomb inside a bouquet of flowers and placed it near the altar beneath the image, during a period of intense anti-Catholic sentiment and legal persecution of the Church in Mexico that would soon escalate into open conflict. The explosion, reportedly heard roughly a kilometer away, shattered windows throughout the basilica, damaged the marble altar steps, and bent a bronze crucifix on the altar backward from the force of the blast. The glass case protecting the tilma was not even cracked, and the image itself sustained no visible damage, a fact widely reported at the time and still commemorated at the basilica today, where the bent crucifix remains on display.
What Examiners Have Reported in the Eyes
Beginning in 1929, the Basilica’s official photographer, Alfonso Marcué González, reported noticing what appeared to be the reflection of a bearded man in the right eye of the image while examining a high resolution photograph, a discovery he was initially asked to keep confidential. In 1951, a separate researcher reported rediscovering the same reflection independently while studying another photograph of the image. Starting in 1956, a series of ophthalmologists, including Dr. Javier Torroella Bueno and Dr. Rafael Torija Lavoignet, examined the eyes directly with an ophthalmoscope, the instrument used to examine living human eyes, and reported that the reflections followed the Purkinje-Sanson optical principle, the pattern by which a living cornea reflects objects in front of it from slightly different angles between the left and right eye. A painted surface does not typically reproduce this kind of optical distortion.
In 1979, Dr. José Aste Tonsmann, an engineer trained at Cornell University who was then working with digital image processing at IBM, applied that technology to high resolution photographs of the eyes, magnifying them roughly 2,500 times their actual size. He reported identifying several human figures within the reflections, a finding he continued to study and publish on for the following two decades, and interpreted as corresponding to the group of witnesses present when Juan Diego first opened his tilma before the bishop.
These findings should be understood for what they are: reports from named researchers using the scientific tools available to them at the time, not formally defined Church teaching, and not claims the faithful are required to accept as a matter of doctrine. What the Church does affirm, through its centuries of papal recognition and the canonization of Juan Diego, is that devotion to Our Lady of Guadalupe under the historical account handed down since 1531 is a legitimate and fruitful expression of Catholic Marian devotion.
A Living Shrine
The image continues to draw enormous numbers of pilgrims to the Basilica of Our Lady of Guadalupe every year, with some reports placing annual visitors above twenty million, making it among the most visited religious sites in the world. Many pilgrims arrive on foot from great distances in the days before her feast, and some complete the final approach to the basilica on their knees as an act of penance and devotion. Whatever conclusions science ultimately reaches about the tilma, its endurance has never been the point. The image exists to point toward Christ, whom Our Lady carries beneath her folded hands.
Continue This Series
Continue with Reading the Symbols of Our Lady of Guadalupe, or return to the Our Lady of Guadalupe Rosary series hub.
