If you want to see the Mona Lisa in real life, your first thought may not be to head to the Pra­do. But accord­ing to a school of thought that has emerged in recent years, the Mona Lisa in Madrid has a greater claim to artis­tic faith­ful­ness than the one in Paris. That’s because researchers have dis­cov­ered com­pelling evi­dence sug­gest­ing that what was long con­sid­ered just anoth­er copy of the most famous paint­ing in the world was­n’t made after Leonar­do had com­plet­ed the orig­i­nal, but con­cur­rent­ly with the orig­i­nal, prob­a­bly by one of his stu­dents. Over half a mil­len­ni­um, in this view, the Prado’s Mona Lisa has retained the col­ors and details the Lou­vre’s has lost, result­ing in its preser­va­tion of Leonar­do’s inten­tions today.

Infrared pho­tog­ra­phy has even revealed, says the nar­ra­tor of the new Inspi­rag­gio video above, that both paint­ings “share the same changes in the orig­i­nal sketch. For years, it has been known that Leonar­do made small cor­rec­tions to the shape of the Mona Lisa’s hands, adjust­ments to the line of the eyes, and sub­tle mod­i­fi­ca­tions to the curve of the face,” the very same cor­rec­tions that were found in the new­ly exam­ined copy.

Unlike oth­er copies, the Prado’s ver­sion uses “incred­i­bly expen­sive pig­ments” such as lapis lazuli—imported from Afghanistan—for the sky. This only became evi­dent dur­ing the 2012 restora­tion, when the back­ground, long hid­den under a thick lay­er of black, was final­ly uncov­ered.

There­after, the Pra­do Mona Lisa was exhib­it­ed along­side the Mona Lisa at the Lou­vre in a tem­po­rary exhi­bi­tion. This gave the pub­lic the chance to see both how sim­i­lar they look, and how dif­fer­ent. Though unde­ni­ably La Gio­con­da, the copy does­n’t seem quite “right,” in large part because it has­n’t dete­ri­o­rat­ed in the man­ner or to the degree of the orig­i­nal. Leonar­do paint­ed it on a poplar wood pan­el that has giv­en way to count­less small cracks, and the lay­ers of yel­low var­nish added over the cen­turies have dark­ened to give the whole image a sepia tone. The result, of course, is the tex­ture and col­or­ing we’ve come to asso­ciate with the Mona Lisa by cease­less expo­sure to her in pop­u­lar cul­ture, even if we’ve nev­er seen any ver­sion hang­ing in any muse­um. If the Prado’s copy real­ly does reflect Leonar­do’s orig­i­nal artis­tic choic­es, we can put at least one hot­ly debat­ed mat­ter to rest: the lady real­ly did have eye­brows.

Relat­ed con­tent:

What Makes Leonardo’s Mona Lisa a Great Paint­ing?: An Expla­na­tion in 15 Min­utes

Did Leonar­do da Vin­ci Paint a First Mona Lisa Before the Mona Lisa?

How Did the Mona Lisa Become the World’s Most Famous Paint­ing?: It’s Not What You Think

Orig­i­nal Por­trait of the Mona Lisa Found Beneath the Paint Lay­ers of da Vinci’s Mas­ter­piece

An Immac­u­late Copy of Leonardo’s The Last Sup­per Dig­i­tized by Google: View It in High Res­o­lu­tion Online

A Chi­nese Painter Spe­cial­iz­ing in Copy­ing Van Gogh Paint­ings Trav­els to Ams­ter­dam & Sees Van Gogh’s Mas­ter­pieces for the First Time

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities and the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les. Fol­low him on the social net­work for­mer­ly known as Twit­ter at @colinmarshall.