evidence: In an alternative version of the quotation, Leonardo is purported to have said "I have offended God and mankind by doing so little with my life." You can even buy a t-shirt featuring the words. [...] In it, Vasari gives an account of Leonardo spending his final moments in the company of King Francis I of France, one of his primary patrons. Notably, Vasari does not actually attribute the words to Leonardo as a direct quotation. Here's what he says, according to an 1879 edition of the book in the original Italian: [...] Ultimately, we don't know what Leonardo da Vinci's last words were. But we do know that the quotation commonly attributed to him is a modified version of the description of a conversation written 50 years after his death by an unreliable historian.