Original: A new building designed by architect Carl Ferdinand Langhans, known as the Königliches Opernhaus (Royal Opera House), was inaugurated the following autumn by a performance of Meyerbeer's Ein Feldlager in Schlesien.
Simplified: It was called Königliches Opernhaus (Royal Opera House), and it opened with a performance of Meyerbeers Ein Feldlager in Schlesien.