Bailly, Jean-Sylvain

(born Sept. 15, 1736, Paris, France—died Nov. 12, 1793, Paris) French astronomer and politician. Noted for his computation of an orbit for Halley's Comet in 1759, he turned to politics with the outbreak of the French Revolution. He was chosen president of the Third Estate in May 1789 and was proclaimed the first mayor of Paris in July. He later lost popularity, particularly after his order to disperse a riotous crowd led to the massacre of the Champ de Mars (1791). He retired but was subsequently arrested, taken before the revolutionary tribunal, and guillotined.

Source: Encyclopedia Britannica