Complex sentence: In the reign of Louis XV, the musicians of the two chapels were united, and oversight was eventually transferred (in 1761) from the Ecclesiastical household to the King's Chamber and the position of "master of the chapel" was eliminated.
Split into simpler sentences: In the reign of Louis XV, the musicians of the two chapels were united. Oversight was eventually transferred (in 1761) from the Ecclesiastical household to the King's Chamber and the position of master of the chapel was eliminated.