La clemenza di Tito
Mammel sang among others the title role of Monteverdi's "L'Orfeo" in Iceland. He was a guest artist at the Theater Freiburg, the Theater Koblenz and the Staatsoper Unter den Linden in Berlin. In 2008 Mammel performed the title role in Mozart's "La clemenza di Tito" at the Opéra de Normandie in Rouen.