This may be the earliest dated picture of the Virgin of the Immaculate Conception. This doctrine, which claimed the Virgin was conceived miraculously without taint of original sin, was controversial but enjoyed increasing popularity in the 15th century, becoming dogma in 1854. Although rejected by the Dominicans, the Franciscans supported it. A standard format and symbolism developed for such pictures. The symbols derive from the Bible, including the Book of Revelation and The Song of Songs. Here, the Virgin\'s purity is symbolised by a lily in a pure crystal glass. The painting, signed and dated 1492, comes from the Franciscan church of San Francesco, Pergola, central Italy.