Bougainville receives permission from Louis XV in 1766 to circumnavigate the globe.

He will become the fourteenth navigator, and the first Frenchman, to sail around the world.

Completion of his mission will bolster the prestige of France following its defeats during the Seven Years' War.

This is the first expedition to circumnavigate the globe with professional naturalists and geographers aboard.

The expedition receives the support of such prominent figures of the time as Charles de Brosses (1709–1777), Comte de Buffon (1707–1788), and Jérôme Lalande (1732–1807).

The purpose of the expedition is to discover new territories available for settlement, to open a new route to reach China, to found new outlets for the French East India Company and, finally, discover acclimatable spices for the Isle de France (now Mauritius).

Bougainville leaves Nantes on November 15, 1766, with two ships: Boudeuse (captain: Nicolas Pierre Duclos-Guyot) and the Étoile (commanded by François Chenard de la Giraudais).

This is a large expedition, with a crew of two hundred and fourteen aboard Boudeuse and one hundred and sixteen aboard Étoile.

Included in the party is the botanist Philibert Commerçon, who will name the flower Bougainvillea, and his valet.

The ship's surgeon will later reveal this person as Jeanne Baré, possibly Commerçon's mistress; she will become the first woman known to circumnavigate the globe.

Other notable people on this expedition are Count Jean-François de Galaup de la Pérouse (member of the crew); the astronomer Pierre-Antoine Veron; the surgeon of Boudeuse Dr. Louis-Claude Laporte; the surgeon of the Étoile Dr. François Vives; the engineer and cartographer aboard the Étoile Charles Routier de Romainville; and the writer and historian Louis-Antoine Starot de Saint-Germain.

The discovery and description of Tahiti by Bougainville in his trip will have a very significant impact on the philosophers of the Enlightenment, including Jean-Jacques Rousseau (1712–1778).

Franz Xavier von Zach publishes Tables of the Sun (Gotha, 1792; new and improved edition, Gotha, 1804), and numerous papers on geographical subjects, particularly on the geographical positions of many towns and places, which he determines on his travels with a sextant.

Zach had studied physics at the Royal University of Pest, served for some time in the Austrian army, and taught at the University of Lemberg (now Lviv, Ukraine).

He lived in Paris in 1780–83, and in London from 1783 to 1786 as tutor in the house of the Saxon ambassador, Hans Moritz von Brühl.

In Paris and London he had entered the circles of astronomers like Joseph de Lalande, Pierre-Simon Laplace and William Herschel.

In 1786 he had been appointed by Ernest II, Duke of Saxe-Gotha-Altenburg, as director of the new observatory on Seeberg hill at Gotha, completed in 1791.

The days of the French Revolution and Republic see many efforts to sweep away various trappings of the ancien régime (the old feudal monarchy); some of these are more successful than others.

The new Republican government seeks to institute, among other reforms, a new social and legal system, a new system of weights and measures (which become the metric system), and a new calendar.

Amid nostalgia for the ancient Roman Republic, the theories of the Enlightenment are at their peak, and the devisers of the new systems look to nature for their inspiration.

Natural constants, multiples of ten, and Latin as well as Ancient Greek derivations form the fundamental blocks from which the new systems are built.

The new calendar is created by a commission under the direction of the politician Charles-Gilbert Romme seconded by Claude Joseph Ferry and Charles-François Dupuis.

They associate with their work the chemist Louis-Bernard Guyton de Morveau, the mathematician and astronomer Joseph-Louis Lagrange, the astronomer Joseph Jérôme Lefrançois de Lalande, the mathematician Gaspard Monge, the astronomer and naval geographer Alexandre Guy Pingré, and the poet, actor and playwright Fabre d'Églantine, who invented the names of the months, with the help of André Thouin, gardener at the Jardin des Plantes of the Muséum National d'Histoire Naturelle in Paris.

As the rapporteur of the commission, Charles-Gilbert Romme presents the new calendar to the Jacobin-controlled National Convention on September 23, 1793, which adopts it on October 24, 1793, and also extends it proleptically to its epoch of September 22, 1792.

It is because of his position as rapporteur of the commission that the creation of the republican calendar is attributed to Romme.

The calendar is often called the "French Revolutionary Calendar" because it is created during the Revolution, but this is somewhat of a misnomer.

Indeed, there was initially a debate as to whether the calendar should celebrate the Great Revolution, which began in July 1789, or the Republic, which was established in 1792.

Immediately following July 14, 1789, papers and pamphlets started calling 1789 year I of Liberty and the following years II and III.

It was in 1792, with the practical problem of dating financial transactions, that the legislative assembly had been confronted with the problem of the calendar.

Originally, the choice of epoch was either January 1, 1789 or July 14  1789.

After some hesitation the assembly had decided on January 2, 1792 that all official documents will use the "era of Liberty" and that the year IV of Liberty had started on January 1, 1792.

This usage had been modified on September 22 , 1792 when the Republic was proclaimed and the Convention decided that all public documents would be dated Year I of the French Republic.

The decree of January 2, 1793 had stipulated that the year II of the Republic began on January 1, 1793; this is revoked with the introduction of the new calendar, which sets September 22, 1793, as the beginning of year II.

The establishment of the Republic is used as the epochal date for the calendar; therefore, the calendar commemorates the Republic, not the Revolution.

In France, it is known as the calendrier républicain as well as the calendrier révolutionnaire.