Henri Jean-Baptiste Grégoire (; 4 December 1750 – 28 May 1831), often referred to as the Abbé Grégoire, was a French Catholic priest, Constitutional bishop of Blois and a revolutionary leader. He was an ardent slavery abolitionist and supporter of universal suffrage. He was a founding member of the Bureau des longitudes, the Institut de France, and the Conservatoire national des arts et métiers. Early life and education Grégoire was born in Vého near Lunéville, France, as the son of a tailor. Educated at the Jesuit college at Nancy, he became curé (parish priest) of Emberménil in 1782. In 1783 he was crowned by the Academy of Nancy for his Eloge de la poésie, and in 1788 by that of Metz for an Essai sur la régénération physique et morale des Juifs. He was elected in 1789 by the clergy of the bailliage of Nancy to the Estates-General, where he soon made his name as one of the group of clerical and lay deputies of Jansenist or Gallican sympathies who supported the Revolution. He was one of the first of the clergy to join the third estate, and thus contributed notably to the union of the three orders. He presided in the session that lasted sixty-two hours while the Bastille was being attacked, and spoke vehemently against the enemies of the nation. He later took a leading role in the abolition of the privileges of the nobility and the Church. Career and contributions Constitutional bishop Under the new Civil Constitution of the Clergy, to which he was the first priest to take the oath (27 December 1790), Grégoire was elected bishop by two départements. He selected that of Loir-et-Cher, but assumed the old title of bishop of Blois, and for ten years (1791–1801) governed his diocese with exemplary zeal. An ardent republican, he strongly supported Collot d'Herbois' motion for the abolition of the monarchy in the first session of the National Convention (21 September 1792) with the memorable phrase "Kings are in morality what monsters are in the world of nature." On 15 November 1792, he delivered a speech in which he demanded that King Louis XVI be brought to trial, and immediately afterwards was elected president of the Convention, over which he presided in his episcopal street dress. During the trial, being absent with other three colleagues on a mission for the union of Savoy to France, he along