Isaac de, was born at Geneva, on the 18th February 1559; his family, which was originally from Dauphiné, having taken refuge in that city after embracing the Reformed religion. He received the rudiments of his education from his father, who was latterly minister of Crest; and his progress was so rapid that at the age of nine he spoke Latin with correctness and fluency. At the age of nineteen he entered upon his academical course at Geneva; and having devoted himself to the study of jurisprudence, theology, and the oriental languages, in 1582 he succeeded his master, Francis Portus, in the chair of Greek. He married Florence, daughter of M. Etienne; and in 1596 accepted the chair of Greek and belles-lettres at Montpellier, where, however, as his salary was ill paid, he remained only two years. He was soon after appointed by Henry IV. to a similar situation in Paris; but his religion, the jealousy of the other professors, and perhaps also his untractable temper, produced misunderstandings and occasioned inconveniences, for which, however, he was indemnified by being appointed librarian to the king, with a salary of four hundred francs. He was one of the commissioners at the conference of Fontainebleau, between Cardinal Du Perron and Duplessis-Mornay, and gave his opinion in favour of the former and against the latter. It is known, indeed, that on various important points he dissented from the tenets of the Reformed church; and he was even suspected of a disposition to reconcile himself to the ancient religion; a suspicion which was strengthened when his son embraced the Romish religion, and became a Capuchin. After the death of Henry IV. Casaubon went to England with Sir Henry Wotton, ambassador extraordinary of King James I., and was received with great favour by that monarch, who gave him two prebends, one at Canterbury and the other at Westminster, and also conferred on him a pension of L200. Casaubon now established himself in England, and died at London on the 1st of July 1614. He was buried at Westminster, where a monument was erected to his memory. The Protestants of France always doubted the sincerity of his attachment to their party; and Pierre Dumoulin, writing to Montague bishop of Bath, said that Casaubon had a great inclination towards popery, and predicted that he would end by changing his religion. This prediction, however, was not verified. Casaubon was an able theologian, a scholar of the first order, a good translator, and an excellent critic. Pithou, De Thou, Heinsius, Gravius, Duperron, and other learned men, have all given him the same character. His Latin is slightly deformed by Gallicisms, and his historical works are not free from inaccuracies. A complete list of his works would of itself fill several columns.

The principal are, 1. In Diogenem Laertium Notæ, 1683, 8vo; 2. Polygini Strangmanus, Gr. et Lat. cum Notis Casauboni, Lyons, 1589, 8vo; 3. Aristotelis Opera, Gr. et Lat. Lyons, 1589; 4. Theophrasti Characteres, Gr. et Lat. Lyons, 1622; 5. Suetonii Opera, cum annotationibus, Paris, 1605, 4to; 6. Persii Satyrae, cum Commentariis, 1605, 8vo; 7. Polygii Opera, Gr. et Lat., Paris, 1609; 8. De Satyrarum Graecorum Poetis et Romanorum Satyrae, libri duo, Paris, 1605, 8vo; 9. Examen contra Baronium, London, 1614, folio; 10. De Libraria Ecclesiastica, liber singularis, 1607; 11. Ad Promontorium Doctorum Epistolæ, London, 1611; 12. Casauboni Epistolæ, the best edition of which is that of Ameloveen, Rotterdam, 1702.

Merle, son of the preceding, was born at Geneva on the 14th of August 1599. He commenced his studies at the Protestant academy of Sedan, but when his father settled in England, he was sent to Christ College, Oxford, and took the degree of M.A. in 1621. He was successively appointed curate of Bledon, Somersetshire, prebendary of Canterbury, and rector of Wickham, and obtained the degree of D.D. from Oxford; but was stripped of his preferments at the Revolution. Cromwell wished him to engage in writing a history of the civil wars, and offered him a gratuity of L400 to assist him in the undertaking; but Casaubon, whose sentiments were unfavourable to the protector, rejected both the proposal and the gift. He refused also a proposal from Queen Christina, who was anxious to appoint him to a high professional office in her dominions. At the Restoration he was rewarded for his fidelity by being reinstated in all his benefices, which he enjoyed till the period of his death in July 1671. He was interred in the cathedral of Canterbury, where a monument was erected to his memory. Casaubon was a pious man, charitable to the poor, of an honest and affable character, and ever ready to communicate the result of his researches. He applied himself principally to criticism, and his erudition was varied, though far from being so profound as that of his father. To the philosophy of Descartes he ascribed the decline of the taste for the belles-lettres, which formed one of the characteristics of his time.

His principal works are, 1. Opuscula Philologicalia libri vii., cum notis et emendationibus, London, 1631, 8vo; 2. Notæ et Emendationes in