This research project is mainly focused on how to reconstruct the middle parts (videlicet haute-contres, tailles and quintes) from French orchestral pieces, which survived only in their reduced forms (featuring primarely dessus and continuo), according to historical examples. By analyzing orchestral excerpts which were edited or copied in both forms, a five voice reconstruction of these diminished works will be produced. Furthermore, there shall be an accompanying report on how those parts were added in the common practice at the time and its relation with current instrumentation (since the aforementioned instruments are not redily available today). In order to fully realize this, it is important to examine these filledout works in a 21st century performance setting. The period to be explored is the one after J.B. Lully’s death until the death of A. Campra, emcompassing the so-called post Lully generation, specifically from 1687 untill 1744.