Charles Pierre Claret de Fleurieu Charles Pierre Claret , comte de Fleurieu ( 2 July 1738 , Lyon – 18 August 1810 ) was a French explorer , hydrographer and politician . He was Minister of the Navy under Louis XVI , and a member of the Institut de France , as well as the brother of the botanist Marc Antoine Louis Claret de la Tourette . Life . Ancien Regime . Fleurieu was born in Lyon . Engaged in the Toulon company of the Garde - marine from the age of 13 and a half on 31 October 1755 , he subsequently took part in the campaigns of the Seven Years ' War — which ended in 1763 — participating in the battles of Mahon , Lagos , and Les Sablettes and rising to brigadier in the " gardes de la marine " company , and then " enseigne de vaisseau " . In suggesting de Fleurieu ' s promotion to ensign , on 23 March 1762 , the Minister wrote to the king : On 1 July 1765 he was made Enseigne de port , and on 27 July he went to Paris to study horology with Ferdinand Berthoud . He took part in a one - year sea campaign to test Berthoud ' s first marine chronometer , in an attempt to beat Britain in the race to find a reliable way to calculate longitude . The chronometers he thus refined with Ferdinand Berthoud for their later experiments were the object of major struggles with the king ' s horologer , Pierre Le Roy . Finally Claret de Fleurieu and Berthoud were entrusted with the task , setting out on the testing expedition from autumn 1768 to 11 October 1769 on the frigate " Isis " under Fleurieu ' s command . The chronometers almost invariably indicated the hour as accurately after the ship had left port , as if they were still on land . Knowing the actual local time at each present location by astronomy , they could easily determine the ship ' s exact position and longitude on a chart . The results of their observations was published in 1773 under the title " Voyage fait par ordre du roi , pour éprouver les horloges marines " ( " Voyage made by order of the king , to test marine chronometers " ) . We can also cite among his major works " le Neptune du Nord " or " l ' Atlas du Cattegat et de la Baltique " , an atlas of the Kattegat and the Baltic Sea that took him 25 years . Made " lieutenant de vaisseau " on 1 October 1773 , then deputy inspector of naval charts and plans , he also became deputy inspector of the naval academy on 15 May 1776 . He was presented to the king and named " capitaine de vaisseau " on 5 December 1776 and soon afterwards director of ports and arsenals in January 1777 , a post heading the fleet ' s organization of matériel , works and movements created specially for him by Louis XVI and one he held for 15 years . In it he directed nearly all planning for naval operations in the 1778 - 83 war against England as part of France ' s involvement in the American Revolutionary War , as well as all the French voyages of discovery such as that of La Pérouse . French Revolution . The king made him " Ministre de la Marine et des Colonies " on 26 October 1790 . He and the king wanted to separate the naval and colonial ministries , but the Assemblée nationale thought otherwise , and he resigned on 15 April 1791 . Later that year he was made guardian of the Dauphin , later Louis XVII . He remained in the Tuileries on 10 August 1792 , in support of Louis XVI right up until the critical point , but fortunately for him the revolutionaries did not discover this . In the midst of the Reign of Terror , in September 1793 , Charles Pierre was arrested due to a letter of recommendation Louis XVI had sent to the Assemblée nationale , published in the " Universal Monitor " on 17 April 1791 , in which he first demanded Charles ' nomination as the Dauphin ' s governor . He remained imprisoned with his wife in the Madelonnettes for 14 months ; they were finally released to find their homes , furniture , lands and resources dispersed and destroyed . A letter to the " section des piques " in the prison . discovered in Robespierre ' s house . speaks of a first arrest , which may suggest Charles was arrested several times and transferred from prison to prison . After the fall of Robespierre he was made a member of the Bureau des longitudes and of the Institut after M . de Bougainville ' s resignation in 1795 . In 1797 ( year V ) he was elected deputy for the Seine in the Council of Ancients under the name Claret - Fleurieu . He remained so until the coup d ' état of 18 Fructidor when he was excluded from the Council . He was elected a member of the Conseil d ' État on 24 December 1799 . First French Empire . On 30 September 1800 , as Minister Plenipotentiary , he signed a treaty of friendship and commerce between France and the United States at Morfontaine , alongside Joseph Bonaparte . A member of the Council of State in 1800 , he presided over its naval section and was interim Minister of the Navy several times during 1803 and 1804 . He was named Quartermaster General of the emperor Napoleon ' s household and of the Imperial civil list on 10 July 1804 . On 24 July 1805 he was elected a member of the Sénat conservateur and made a Grand Officer of the Legion of Honor . On 1 August 1805 , he was made Governor of the Tuilleries and the Louvre , taking the oath before the Emperor on 8 September that year . On 2 February 1806 he was elected one of the seven senators who composed the Council of Administration within the Senate for that year . In 1808 he was made Councilor of State for life and an Imperial Count . On 7 September of that same year , Napoleon put him in charge of the investigation into the French defeat at the Battle of Trafalgar . He died in Paris from a devastating cerebral hemorrhage , a few seconds after embracing his two daughters . Napoleon rewarded his services by giving him a state funeral and having his remains transferred to the Panthéon . Marriage and issue . At 54 he married Aglaé - Françoise Deslacs d ' Arcambal ; they had one son who died young , Caroline ( Madame de Saint - Ouen , from whom his descendants trace their line ) and a second daughter . Works . He also edited the " Voyage autour du monde " which was written in 1790 and 1792 by Étienne Marchand , year VI ( 1798 ) .