Complex sentence: He accepted in 1680 the appointment of librarian to François-Chrétien de Lamoignon, advocate-general to the parlement of Paris, of whose library he made a "catalogue raisonné" (35 vols.), all written with his own hand.
Split into simpler sentences: He accepted in 1680 the appointment of librarian to François-Chrétien de Lamoignon, advocate-general to the parlement of Paris. He made a "catalogue raisonné" (in 35 vols.) of its library, all written with his own hand.