Despite being a cradle-Catholic, I only learned of Our Lady depicted as Mater Admirabilis a few years ago. This is her story:
"In 1844, at the Trinita dei Monti convent in Rome, a French novice by the name of Pauline Perdrau received permission from the Mother Superior to paint a fresco of Our Lady. She spent months painting working on the fresco. Despite her effort, the image was not very good, and the Mother Superior covered it with a curtain to hide it. Two years later, Pope Pius IX was visiting the convent, and out of curiosity drew back the curtain. The painting had been transformed and beautiful. He exclaimed “Mater Admirabilis!,” which means “Mother Most Admirable!” Word quickly spread, and many began a devotion to Mother Most Admirable. Under this title, Our Lady began to grant favors and miracles, and the Feast of Mater Admirabilis is celebrated on October 20th. 