Silvano Vinceti claims he has found the letter "S" in the woman's left eye, the letter "L" in her right eye, and the number "72" under the arched bridge in the backdrop of the painting. According to the researcher, the symbols open up new leads to identifying the model, dating the painting - and show that Leonardo had an interest in religion and mysticism.
The symbols are not visible to the naked eye. Vinceti said Wednesday they are "very small, painted with a tiny brush and subjected to the wear and tear of time."
A Leonardo scholar has expressed doubt on the new findings, calling them "unsubstantial."
