Prince Fielder walks to the plate, and the 21st Century gives way to the 18th. For his walk-up music for his at-bats, Fielder now has the public-address system at Comerica Park play a burst of Mozart. Fielder said the music came from “Requiem,” a huge piece Wolfgang Amadeus Mozart worked on in the final year of his life, 1791. He hadn’t finished it when he died that December at 35. Fielder said his path to choosing “Requiem” began when he found out that Torii Hunter listened to classical music leading up to games. Fielder sought classical music used in movies. “I thought about how all the scores for the ‘Batman’ movies are pretty cool,” Fielder said. “So I went on Pandora and typed in movie scores, and I thought, ‘This isn’t bad.’ “I heard one, and I liked it.” Fielder was impressed in spring training that Hunter, his new teammate, “was so seasoned and had so much energy early in the morning.” So he said he told Hunter, “I’m going to do everything you do so I can play as long as you.” Fielder, 28, is nine years younger than Hunter. Mozart wrote “Requiem” 80 years before what we now regard as the dawn of organized major league baseball. But every time Fielder comes to bat at Comerica now, Mozart is in the big leagues.