Leonardo’s sexuality was always an unclear construct. Regardless of whom he preferred romantically, many of his portraits are absolutely filled with sensuality. There is something so obvious, so crude, about Leonardo da Vinci 's portrait of Cecilia Gallerani that it might seem beneath discussion. The 16-year-old mistress of the ruler of Milan, Ludovico Sforza, is stroking an ermine. The creature is white, furry and bony. Scholars have written reams about this ermine 's significance as an allegory