Thank you all for the answers.  

 This is another article written by Professor of the History of Art, David Summers: "Leonardo da Vinci was one of the greatest painters and most versatile geniuses in history. [...] Because Leonardo excelled in such an amazing number of areas of human knowledge, he is often called a universal genius. [...] His inventiveness, versatility, and wide-ranging intellectual curiosity have made Leonardo a symbol of the Renaissance spirit." 

 Other encyclopedic material of an eminent scholar. See: http://photo.pds.org:5005/advanced/article?id=ar319880&st;=leonardo+da+vinci