Possible Clues:

• Powerful Renaissance banking family
• Riviera location here in France and house in Florence
• In the matter of having got it wrong in the laboratory
• Renowned family of Italian history
• Italian family doctor visits one
• Italian doctors who ministered to Caterina's victims?
• Big name in Renaissance patronage
• Renaissance patrons of Sir Thomas Browne
• Caterina de' --
• Florentine ruler