He must have lost his head a little for Robert's mother was called Berthe in the first act and Rosalie in the third.

However, the answer might be that she changed her name when she became religious.
Later, Scribe was put to another no less difficult test with _L'Etoile du Nord_.

When Meyerbeer was the conductor at the Berlin Opera, he wrote on command _Le Camp de Silesie_ with Frederick the Great as the hero and Jenny Lind as the musical star.

As we know, Frederick was a musician, for he both composed music and played the flute, while Jenny Lind, the Swedish nightingale, was a great singer.

A contest between the nightingale and the flute was sure to follow or theatrical instinct is a vain phrase.