On May 14, 2023, Grand Duke Henri, Grand Duchess Maria Teresa, Prince Felix, Princess Claire and Prince Louis attended the traditional pontifical mass at Notre-Dame Cathedral in Luxembourg that was held as part of 2023 Catholic Octave celebrations. The Octave is one of Luxembourg's major annual religious celebrations. It starts on the 3rd Sunday after Easter and closes with the Octave Procession on the 5th Sunday after Easter.