At the “ Raphael: Sublime Poetry ” exhibition at the Metropolitan Museum of Art one masterpiece is more jaw-dropping than the next. The exquisite Madonnas, the monumental tapestries, the bravura drawings. So many of them. Walking through the quiet galleries before the museum opened to the public the other day (perks of the job), I kept wondering: What does it take to put together an astounding exhibition like this? I asked Robert Simon , a prominent Old Master art dealer in New York, who unearthed the painting Salvator Mundi that was later authenticated and sold as a Leonardo for $450 million. “Money and power,” was his answer. “Only the Met could do such a show.” An Epic Survey  The largest survey dedicated to the Renaissance master in the U.S. includes 33 of his paintings and 142 works on paper. About 60 public institutions from 11 countries sent their treasures by the man born Raphael Sanzio da Urbino (1483–1520).…