The Birth Of Venus by Sarah Dunant

Alessandra is not quite fifteen when her prosperous merchant father brings a young painter back with him from Holland to adorn the walls of the new family chapel. She is fascinated by his talents and envious of his abilities and opportunities to paint to the glory of God. Soon her love of art and her lively independence are luring her into closer involvement with all sorts of taboo areas of life. On excursions into the streets of night-time Florence she observes a terrible evil stalking the city and witnesses the rise of the fiery young priest, Savanarola, who has set out to rid the city of vice, richness, even art itself.
Alessandra must make crucial decisions about the shape of her adult life, as Florence itself must choose between the old ways of the luxury-loving Medicis and the asceticism of Savanorola. And through it all, there is the painter, whose love will change everything.