Why would the physician Sir Edward Throckle, summmoned from long retirement to Henry VIII's court, respond by committing suicide? That's only the curtain-raiser to this feast of riddles when Henry's advisor Cardinal Wolsey dispatches his nephew Benjamin Daunbey and Daunbey's rascally servant Roger Shallot (The Grail Murders, 1994, etc.) to Florence as envoys to the Albrizzi family of merchants, bent on vengeance for the murder of Francesco Albrizzi. How could someone have shot Francesco in a crowded Cheapside market and still kept the weapon, a newfangled and cumbersome arquebus, concealed? Which of Francesco's relatives--his obliging widow, his ambitious brother, his bullying son, his nymphomaniac daughter, her scheming husband--could have killed the head of the family? (Think fast; most of the grieving family will be wiped out in a climactic massacre.) And what does Daunbey's and Shallot's investigation--carried out with the help of a comely, sharp-tongued family jester named Maria--have to do with their other errand in Florence, a secret legation to Cardinal Giulio de' Medici, who has his eye on the Papacy and doesn't mind ruffling whatever robes are in his way? Shallot's fourth adventure is one of his liveliest, if you can overlook its narrator-hero's tiresome encomiums on Queen Elizabeth's breasts and the love-child she bore him.