0707,
My remarks earlier contained a minor typo.
"need" should have said "needed".
Today, or at least when I went to college in Canada, we called the arts students "artsies", and we did not take them seriously. This distinction did not exist in Leonardo's day. Paintings, sculptures, churches and fortifications were made by the same group of craftsmen, who sought out contracts, hired apprentices and assistants, and generally managed projects. I believe that it is one of Boticcelli's (sp?) pictures has an angel on it that was almost certainly painted by his apprentice, Leonardo.
The usual date for the end of the Renaissance is that of the sack of Rome by Imperial troops in 1527. There was not a whole lot of burning of heretics prior to this date, although things picked up once the Catholics and Protestants started to work against each other. The Great Witch Hunt took place mostly in Germany between XVI and XVIII. There were executions in France, England and Italy. Apparently, the Spanish Inquisition had higher standards of evidence, and did not burn any.
The Renaissance period was a disaster for Italy, ending in widespread devastation, and conquest by foreigners. I do not know that much about the life of Leonardo da Vinci, but I suspect that working for the King of France would have placed him in far more danger in Italy than any religious beliefs he may have held.
JHG