Annunciation by Leonardo da Vinci was painted, with Andrea del Verrocchio, circa 1472–1475. The angel holds a Madonna lily, a symbol of Mary's virginity and of the city of Florence. It is supposed that Leonardo originally copied the wings from those of a bird in flight, but they have since been lengthened by a later artist. When Annunciation came to the Uffizi in 1867, from the monastery of San Bartolomeo of Monteoliveto, near Florence, it was ascribed to Domenico Ghirlandaio, who was, like Leonardo, an apprentice in the workshop of Andrea del Verrocchio. In 1869, some critics recognized it as a youthful work by Leonardo di ser Piero da Vinci. Verrocchio used lead-based paint and heavy brush strokes. He left a note for Leonardo to finish the background and the angel. Leonardo used light brush strokes and no lead. When the Annunciation was x-rayed, Verrocchio's work was evident while Leonardo's angel was invisible. The marble table, in front of the Virgin, probably quotes the tomb of Piero and Giovanni de' Medici in the Basilica of San Lorenzo, Florence, which Verrocchio had sculpted during this same period.