Opera singer and conductor Peter Schreier has died in Dresden, Germany at age 84. The dpa news agency reported Thursday that he died Wednesday, citing his longtime secretary. Schreier was in demand on opera stages all over the world. He performed at the Berlin State Opera in his native East Germany. He also sang at Milan’s La Scala and for 25 years at the famed Salzburg Festival. One of Schreier’s specialties was performing and recording the songs of composers Franz Schubert and Robert Schumann. Dpa didn’t report a cause of death, but said Schreier had suffered heart trouble including bypass surgery in past years.