The place where the basilica now stands was a holy place long before the Spanish conquered Mexico. It is called the Hill of Tepeyac. At the site there was a temple devoted to the mother goddess called Tonantzin. Later, the Spanish destroyed the temple and built a nearby chapel. But the destruction of the temple couldn’t prevent the natives from pouring into the site.
Ten years after the Spanish conquered Mexico, a local peasant named Juan Diego, who had recently converted to Christianity, had a vision said to be Our Lady in the same area, who asked for a chapel to be built in the place. People from all over Mexico rallied to the chapel to worship the shrine, and it is reported that many miracles occurred. Nevertheless, the natives kept calling Our Lady by the name of Tonantzin, the ancient mother goddess revered by the native population. This gave rise to the doubts of the Franciscan friars, who were convinced that the veneration of the holy image was a pagan cult.
Something similar also happened in Enna. In  fact, Our Lady, who is the patron saint of Enna, replaced the ancient cult of Demeter, who was the town’s mother goddess. The celebration in honor of Our Lady happens on July second every year, the same time when the old pagan cult of Demeter was celebrated. People of Enna today still invoke the name Kore, who was Demeter’s daughter.
In my opinion, it doesn’t matter the name you give to God; what matters is the spiritual feeling that radiates from the worshipper. So you can call God Allah, Brahma, Vishnu, or Shiva without losing the purity of your heart. Jesus and the Virgin Mary are beyond time, as they existed before time, long before coming into human history. They also existed in the pagan era and were worshipped differently.
The Virgin Mary appeared to Juan Diego in the form of a crossbreed maiden, and in the same place where the Spanish had destroyed the temple dedicated to the goddess Tonantzin. That means that nobody is allowed to destroy others’ temples, even if they are considered pagan. In fact, religion and spirituality are not related to a particular cult. Over the years people have given various names to God and worshiped Him in different ways, but it doesn’t entitle anybody to resort to violence to make one religion prevail over another.
As for the holy image imprinted on Juan Diego’s cloak, it was kept for some time by the Franciscan friars until it passed under the custody of the diocesan priests. With the passing of time, possibly in good faith, the original image was retouched in some spots. For instance, the crescent on which the Virgin Mary stands was painted with silver. Apparently, nowadays the retouches have discolored naturally, while the original image is still unaltered.

This is an excerpt from A Hidden Sicilian History by Ettore Grillo
Ettore Grillo, author of these books:
– A Hidden Sicilian History
– The Vibrations of Words
-Travels of the Mind
http://www.amazon.com/author/ettoregrillo