Times change. A century ago, Pope Pius X issued a pastoral letter against the tango, condemning it as degenerate, immoral, pagan. Today, Pope Francis insists that he likes it, that it lives deep inside him, that he often danced it in Argentina as a young man. Punctuating this striking reversal of opinion, hundreds of tango dancers flash-mobbed St. Peter’s Square on the pontiff’s birthday in December, twirling around on the cobblestones of the Via della Conciliazione in what the Catholic Church once would have called an obscene act. “I see the ‘tangeros’ are here,” Francis exclaimed, greeting the dancers with an amiable welcome.