Complex sentence: He collaborated with L.-B. Desormery to rewrite the second act of François Lupien Grenet's "opéra-ballet" "Le triomphe de l'harmonie": their work was performed at the Opéra in 1775 titled "Hylas et Eglé".
Split into simpler sentences: He collaborated with L.-B. Desormery to rewrite the second act of François Lupien Grenet's "opéra-ballet" "Le triomphe de l'harmonie". Their work was performed at the Opéra in 1775 under the title "Hylas et Eglé".