Our Lady of Guadalupe (The Tilma of Juan Diego)

The tilma of Juan Diego is the most venerated image in the Americas: a cloak about 170 by 105 centimeters, of coarse agave fiber, bearing the figure of a dark-skinned woman in a blue-green mantle, ringed with golden rays, standing on a crescent moon held up by an angel.

According to the traditional account, the Virgin appeared four times to a recently baptized indigenous man, Juan Diego, in December 1531, asked for a church on Tepeyac hill, and — when the bishop wanted a sign — sent Juan Diego back with his cloak full of out-of-season roses. When he opened it before Bishop Zumárraga, the image was on the cloth. For nearly five centuries it has been at the heart of Mexican Catholic identity.

The documentary record

Juan de Zumárraga, first bishop of Mexico, is the man the story places at the center of the events: he is said to have received the cloak and seen the roses fall. Zumárraga left a large body of letters and reports — he wrote constantly about the evangelization of New Spain, about the indigenous converts, and about his own work — and never once mentions the image. No Spanish document describes the apparition until decades after the fact.

The earliest full narrative is the Nican Mopohua, the Nahuatl account traditionally attributed to Antonio Valeriano. Its manuscript is dated to roughly the mid-1550s, and it was not printed until 1648 — more than a hundred years after 1531. Working through the sources, the historians Stafford Poole and D.A. Brading conclude that the apparition story took shape gradually over the intervening century, growing up around a devotional image that already existed at Tepeyac.

What the image is made of

The cloth has been examined more than once. In 1982 José Sol Rosales, a restorer at Mexico's national institute of fine arts (Instituto Nacional de Bellas Artes), was given access to study the tilma. He reported a prepared white ground beneath the image and ordinary pigments of the period worked in tempera — soot from burned ocote, calcium sulfate, cochineal red, copper and iron oxides — along with areas of touch-up and repainting. His conclusion was that the image is a human-made painting in a recognizable style. Catholic commentators dispute the report.

Philip Callahan — a USDA entomologist and University of Florida professor — photographed the tilma under infrared light in 1981. He reported that he could find no underdrawing or sizing beneath the central figure. In the same work, Callahan identified the gold rays, the stars on the mantle, the moon, the angel, and the decorative border as later additions, painted on by human hands. Joe Nickell notes that Callahan also found no sketch lines under the parts he judged to be retouched.

One claim that recurs in devotional literature holds that the Nobel chemist Richard Kuhn analyzed the tilma and pronounced its colors made of no known pigment. No such study exists. Kuhn won his Nobel Prize in 1938 and died in 1967, and no record places him or his samples anywhere near the cloth.

The figures in the eyes

A separate strand of the case concerns the Virgin's eyes. In 1979 José Aste Tönsmann, an IBM engineer with a doctorate from Cornell, magnified photographs of the eyes and reported seeing reflected human figures in them — eventually a whole scene of some thirteen people, which he interpreted as the moment the cloak was opened before the bishop. The claim depends on extreme magnification and image processing of a coarse, much-handled weave, and it has not been independently reproduced. The investigators Joe Nickell and John Fischer examined it in 1985 and concluded that the "figures" are the mind finding shapes in random texture.

The cloth's survival

The cloth itself has lasted close to five centuries — roughly 490 years — much of that time unglassed and exposed to candle smoke, incense, and handling, which is unusual for an agave-fiber cloak that would ordinarily decay in decades. That longevity has no settled explanation.