Jean Sylvain Bailly (; 15 September 1736 – 12 November 1793) was a French astronomer, mathematician, freemason, and political leader of the early part of the French Revolution. He presided over the Tennis Court Oath, served as the mayor of Paris from 1789 to 1791, and was ultimately guillotined during the Reign of Terror.
Scientific career
Born in Paris, Bailly was the son of Jacques Bailly, an artist and supervisor of the Louvre Palace, and the grandson of , also an artist and court painter. As a child he originally intended to follow in his family's footsteps and pursue a career in the arts. He became deeply attracted to science, however, particularly astronomy, by the influence of Nicolas de Lacaille. An excellent student with a "particularly retentive memory and inexhaustible patience", he calculated an orbit for the next appearance of Halley's Comet (in 1759), and correctly reduced Lacaille's observations of 515 stars. He participated in the construction of an observatory at the Louvre. These achievements along with others got him elected to the French Academy of Sciences in 1763. Due to his popularity amongst the scientific groups, in 1777, Bailly received Benjamin Franklin as a guest in his house in Chaillot. Soon after he was elected inaugural president of the National Assembly (3 June 1789) In the National Assembly (French Revolution) Bailly was one of the deputies who secured the passage of a decree that declared Jews to be French citizens on 17 September 1791. He was met with threats and ridicule for this action. This decree repealed the special taxes that had been imposed on the Jews, as well as all the ordinances existing against them.
Bailly was a member of the Club de 1789, one of the best-known societies at the time.</blockquote>
Food crisis
During the early years of the French Revolution, Paris was going through a major food shortage. Bailly's actions to circumvent the situation were of great importance in keeping the revolution alive. Bailly had deputies gather grain that was being hoarded, made the sale of wheat mandatory by farmers, and helped the bakers by making them first in line in the village markets. He allowed investors to begin the purchasing of church property. Bailly soon heard of a gathering at the Champ de Mars, where citizens were meeting to sign petitions calling for the overthrow of the King. Imposing martial law, he ordered the National Guard to disperse the large riotous assembly that had gathered. A violent response ensued and many people died, for which Bailly, along with Lafayette, was considered responsible. What was to become known as the Champ de Mars Massacre was taken by the revolutionaries as an exemplar for oppression by the government. It was the revival of this event as a part of republican heritage after 10 August 1792, as well as a campaign of municipal persecution led by Marat, that ultimately resulted in Bailly's execution, as well as that of "many of his colleagues".