Alessandro Cagliostro, Count (1743-1793), Italian alchemist and impostor, was born at Palermo on the 8th of June 1743. Giuseppe Balsamo - for such was the "count's" real name - gave early indications of those talents which afterwards gained for him so wide a notoriety. He received the rudiments of his education at the monastery of Caltagirone in Sicily, but was expelled from it for misconduct and disowned by his relations. He now signalized himself by his dissolute life and the ingenuity with which he contrived to perpetrate forgeries and other crimes without exposing himself to the risk of detection. Having at last got into trouble with the authorities he fled from Sicily, and visited in succession Greece, Egypt, Arabia, Persia, Rhodes - where he took lessons in alchemy and the cognate sciences from the Greek Althotas - and Malta. There he presented himself to the grand master of the Maltese order as Count Cagliostro, and curried favour with him as a fellow alchemist, for the grand master's tastes lay in the same direction. From him he obtained introductions to the great houses of Rome and Naples, whither he now hastened.
At Rome he married a beautiful but unprincipled woman, Lorenza Feliciani, with whom he travelled, under different names, through many parts of Europe. It is unnecessary to recount the various infamous means which he employed to pay his expenses during these journeys. He visited London and Paris in 1771, selling love-philtres, elixirs of youth, mixtures for making ugly women beautiful, alchemistic powders, etc., and deriving large profits from his trade. After further travels on the continent he returned to London, where he posed as the founder of a new system of freemasonry, and was well received in the best society, being adored by the ladies. He went to Germany and Holland once more, and to Russia, Poland, and then again to Paris, where, in 1785, he was implicated in the affair of the Diamond Necklace (q.v.); and although Cagliostro escaped conviction by the matchless impudence of his defence, he was imprisoned for other reasons in the Bastille. On his liberation he visited England once more, where he succeeded well at first; but was ultimately outwitted by some English lawyers, and confined for a while in the Fleet prison.
Leaving England, he travelled through Europe as far as Rome, where he was arrested in 1789. He was tried and condemned to death for being a heretic, but the sentence was commuted to perpetual imprisonment, while his wife was immured in a convent. He died in the fortress prison of San Leo in 1795.
The best account of the life, adventures and character of Giuseppe Balsamo is contained in Carlyle's Miscellanies. Dumas's novel, Memoirs of a Physician, is founded on his adventures; see also a series of papers in the Dublin University Magazine, vols. lxxviii. and lxxix.; Memorial, or Brief for Cagliostro in the Cause of Card. de Rohan, etc. (Fr.) by P. Macmahon (1786); Compendio della vita e delle gesta di Giuseppe Balsamo denominato il conte di Cagliostro (Rome, 1791); Sierke, Schwarmer und Schwindler zu Ende des XVIII. Jahrhunderts (1875); and the sketch of his life in D. Silvagni's La Corte e la Società Romana nei secoli XVIII. e XIX. vol. i. (Florence, 1881).