Not so, says Natali, who argues instead that Andrea chose a simple but culturally vibrant life in a circle of like-minded friends -- intellectuals and common folk who practiced material austerity and humility. How can we label as timid an artist who painted a fresco cycle in Florence's most prestigious sacred institution when he was barely twenty years old? asks Natali. How irresolute was the man who accepted an open-ended invitation from French king Francis to join his court in an era when few artists left Florence; who -- amid rigid orthodoxy and accusations of