Leonardo, Letter to the Duke of Milan by Dr. David Drogin Leonardo da Vinci, Letter to the Duke of Milan Cite this page Cite this page as: Dr. David Drogin, "Leonardo, Letter to the Duke of Milan," in Smarthistory, December 7, 2015, accessed March 19, 2024, https://smarthistory.org/leonardo-letter-to-the-duke-of-milan/.