Seventeenth-century Roman art at its fullblown, operatic peak often proves too rich for puritanical northern tastes. And no artist was ever more Baroque than Gian Lorenzo Bernini, the supreme maestro of the idiom. But I love his work, which is why, on a spare afternoon in Rome before Christmas, I strolled over to the Borghese Gallery where the largest array of Bernini sculpture ever assembled is currently on view.