Marat, JEAN PAUL, one of the most prominent figures in the French Revolution, was born at Boudry in Neuchâtel, May 24, 1743, eldest child of Jean Paul Mara, a physician and native of Cagliari, who had married Louise Cabrol, a Genevan Protestant. He studied medicine at Bordeaux, next went to Paris, to Holland, and to London, where for some time he practised his profession with success, and published a materialistic Philosophical Essay on Man (1773), sharply attacking Helvétius, and anonymously a political essay, The Chains of Slavery (1774). In 1775 he paid a visit to Edinburgh, and was made on June 30, on the recommendation of certain Edinburgh physicians, M.D. of St Andrews University; and it hardly admits of doubt that he was not the John Peter le Maître, alias Maire, alias Mara, who got five years at Oxford assizes in March 1777 for stealing coins and medals. For in June 1777 his character and reputation as a physician and oculist stood so high that he was made brevet-physician to his guards by the Comte d'Artois, afterwards King Charles X.—an office which he held till 1786. Meantime he continued his scientific work in optics and electricity, attracting the attention of Franklin and Goethe, but the Académie des Sciences refused him admission on account of his attack on Newton. Further writings were his anonymous Plan de Législation Criminelle (1780), a translation of Newton's Optics (1787), and Mémoires Académiques, ou Nouvelles Découvertes sur la Lumière (1788).
But all Paris was now infected with the fever of revolution, and Marat flung himself with characteristic ardour into the war of pamphlets, and at length in September 1788 established his famous and infamous paper, L'Ami du Peuple. Throughout he fought ever for his own hand, with bleary-eyed honesty and indomitable persistence, constantly croaking of treachery in high places, and denouncing with feverish suspiciousness in turn Necker, Bailly, Lafayette, the king, Dumouriez, and the Girondins. His virulence provoked the most vehement hatred, and covered his own head with calumnies which survived for generations; but it made him the darling of the scum of Paris, and placed great power in his hands at some of the most momentous crises of the Revolution. His printing-press had to be cunningly concealed from Lafayette's police, twice at least he had to flee to London, and once he was forced to hide for a time in the sewers of Paris, where he contracted a loathsome skin disease, yet was tended with affectionate faithfulness by Simonne Evrard, whom he had married 'one fine day in presence of the sun.' His sufferings deepened his frenzied hatred and suspicion of constituted authority, and there can be no doubt that on his head rests in great measure the guilt of the infamous September massacres. He was elected to the Convention as one of the deputies for Paris, and was perhaps the most unpopular man within the house, where indeed his influence never became more than contemptible. On the declaration of the republic he started his paper anew under the title Journal de la République Française. After the king's death his last energies were spent in a mortal struggle with the Girondins, who subscribed their own downfall when their formal accusation of Marat failed before the tribunal. But it was the tribune's last triumph. He was dying fast of the disease he had contracted in the sewers, and could only write sitting in his bath. There his destiny reached him through the knife of Charlotte Corday (q.v.), in the evening of the 13th July 1793. His body was committed to the Panthéon with the greatest public honours, to be cast out but fifteen months later amid popular execration.
See the Histories of the French Revolution by Mignet, Thiers, Michelet, Louis Blanc, Carlyle, Von Sybel, and H. Morse Stephens; Bougeart, Marat, l'Ami du Peuple (2 vols. 1864); Bax, Marat, the People's Friend (1900); but especially the works by F. Chevremont, Marat, Index du Bibliophile (1876); Placards de Marat (1877); and Marat, esprit politique, accompagné de sa vie scientifique, politique, et privée (2 vols. 1881).