The expression "fig leaf" is widely used figuratively to convey the covering up of an act or an object that is embarrassing or distasteful with something of innocuous appearance, a metaphorical reference to the Biblical Book of Genesis in which Adam and Eve used fig leaves to cover their nudity after eating the forbidden fruit from the tree of the knowledge of good and evil. Some paintings and statues have the genitals of their subjects covered by a representation of an actual fig leaf or similar object, either as part of the work or added afterward for perceived modesty. In Ancient Greek art, male nakedness, including the genitals, was common, although the female vulval area was generally covered in art for public display. This tradition continued in Ancient Roman art until the conversion of the Roman Empire to Christianity, when heroic nudity vanished. During the Middle Ages, only the unfortunate (most often the damned) were usually shown naked, although the depictions were then often rather explicit. Adam and Eve were often shown wearing fig or other leaves, following the Biblical description. This was especially a feature of Northern Renaissance art. From about 1530, the developing reaction to Renaissance freedoms and excesses that led to the Council of Trent also led to a number of artworks, especially in churches or public places, being altered to reduce the amount of nudity on display. Often, as in the famous case of Michelangelo's The Last Judgement, drapery or extra branches from any nearby bush was used. This has been dubbed the "fig leaf campaign". For free-standing statues this did not work well, and carved or cast fig leaves were sometimes added, such as with the plaster copy of Michelangelo's David displayed in Victorian era London. Historian Daniel J. Boorstin said that: The age of the rising middle class in Victorian England was, or course, the age of the fig leaf. "The fig leaves of decent reticence" which Charles Kingsley described were applied not only to statuary but to literature as well.