Balthazar Lieutaud, maître in 1749.
Ferdinand Berthaould, maître horloger in 1754.

BALTHAZAR LIEUTAUD
Son of the ebeniste Charles Lieutaud, maker of clocks and part of the privileged enclosure of Saint-Jean de Latran, Balthazar Lieutaud became maître on 20 March 1749. Living on the Île de la Cité in the rue de la Pelleterie, and in 1772 in the rue d'Enfer, Balthazar Lieutaud regularly worked for the clock-makers Viger, Baillon, Dutertre, Balthazard, Voisin, Gudin, Lepaute, Robin, etc. Berthoud commissioned Lieutaud to make a multitude of clock cases throughout his career, their fruitful collaboration resulting in some of the most elaborate designs of the late 18th century; see. The Metropolitan Museum of Art, New York (inv. no. 2016.28a–e) and The Collections of Barons Nathaniel and Albert Von Rothschild; Christie's, London, 8 July 1999, lot 207. Lieutaud equally worked with Caffieri, and with the bronziers Charles Grimpelle and Edme Roy. After his death in 1780 his wife continued the atelier until 1784.

FERDINAND BERTHOUD
Ferdinand Berthoud was one of the greatest French clockmakers of the 18th century. He was born in Placemont, the son of Jean Berthoud, an architect and judiciary. In 1741 he was bound over to his brother, Jean-Henri, with whom he served a three year apprenticeship before leaving for Paris where he worked with the great master Julien Leroy (1686-1759).
On 24 July 1764 he was appointed Horloger Mécanicien de sa Majesté et de la Marine ayant l'inspection de la construction des horloges Marine with an annual stipend of 3,000 livres that increased to 7,000 by 1782. The position was of considerable importance at the time when the race to construct a timepiece capable of finding longitude at sea was the social and political talk of all western Europe. From 1766 he designed all the marine clocks and watches used on the king's ships. Later in the same year he was appointed a member of the Royal society of London and later a Chevalier de la Légion d'Honneur. In 1786 he was a member of the commission to establish a Royal clock factory and in 1793 he was a member of the Temporary Commission for the Arts. Berthoud's writings covered more than 4,000 quarto pages with more than 120 engraved plates from drawings by his own hand; his most important works included: Essai sur l'Horlogerie (1763), Traite des Horloges Marines (1773), De la Measure de Temps (1787) and Histoire de la Measure du Temps par les Horloges (1802).