Question: when did vasari write lives of the artists
Answer: Often called `` the first art historian '' , Vasari invented the genre of the encyclopedia of artistic biographies with his Le Vite de ' più eccellenti pittori , scultori , ed architettori ( Lives of the Most Eminent Painters , Sculptors , and Architects ) , dedicated to Grand Duke Cosimo I de ' Medici , which was first published in 1550 .