Complex sentence: With rehearsals for "Les martyrs" not planned until early 1840, the composer had time to write yet another opera, which became "La fille du régiment", his first written directly to a French text.
Split into simpler sentences: With rehearsals for "Les martyrs" not planned until early 1840, the composer had time to write yet another opera. This became "La fille du régiment", his first written directly to a French text.