Jules (properly Mazzarino, Giulio), son of Pietro Mazzarino, a noble Sicilian, was born at Piscina, in the Abruzzo, on the 14th of July 1602. Having received his elementary education at Rome, he passed into Spain with the Abbé, afterwards Cardinal, Girolamo Colonna, at the age of seventeen, where he attended courses of law in the universities of Alcalá and Salamanca. But he soon abandoned jurisprudence in order to embrace the military profession, and in 1625 was sent, with the rank of captain, into the Valtelline, where the pontiff then had an army. From this time he began to display his talents for diplomacy. The generals of his Holiness, Conti and de Bagni, sent him successively to the Duca de Feria, general of the Spaniards, and to the Marquis de Cœuvres, afterwards Marshal d'Estrees, who commanded the French troops; and in both missions he acquitted himself in such a manner as to merit the commendations of these chiefs. He then returned to Rome, where he resumed the study of jurisprudence, and took his doctor's degree. But the disputed succession to the duchies of Mantua and Montferrat having kindled up a new war, he quitted law for diplomacy, in which line nature had peculiarly qualified him to excel. The competitors were the Duc de Nevers, whose cause was espoused by the court of France, at which he resided, and the Duca de Guastalla, who was supported by the emperor, the King of Spain and the Duke of Savoy. The pope, desirous to prevent a war, of which Italy was about to become the theatre, sent Cardinal Sacchetti to Turin to act in favour of the Duc de Nevers; and Mazarin accompanied him in this mission. Sacchetti returned to Rome unsuccessful, leaving to Mazarin the title of internumcio, with power to continue the negotiations, and to effect a peace. Mazarin first saw Louis XIII. at Lyons in 1630, and had a long conference with Cardinal Richelieu. The cardinal entertained the highest opinion of him, and feeling that France wanted an able and devoted man in Italy, he succeeded in gaining the young diplomatist, who from this time openly showed himself favourable to the interests of France. He returned to Italy without having obtained any success in his mission, and the war continued; but the Duke of Savoy having died, his son gave his entire confidence to Mazarin, who immediately resumed the work of peace with fresh ardour. The Spaniards were besieging Casale, and the French wished to relieve the place; but by negotiating with the chiefs of both armies he induced them to consent to an armistice for six weeks. When this truce had expired he demanded a prolongation, which the French refused, and at the same time prepared to attack the lines. Mazarin then proposed a treaty, in which they stipulated the hardest conditions. To engage them to relax in their demands, he represented the formidable state of the Spanish army, and the hazard of an attempt to force their entrenchments; but failing to persuade them, he passed over to the Spaniards, reported to them the conditions required by the French, and, still employing the same logic, urged the superiority of the French, and their ardent desire for the combat. This time he succeeded. The Spanish general assented to everything. Mazarin immediately quitted the Spanish trenches, and riding at full gallop towards the French, regardless of the balls which whistled around him, waved his hat, exclaiming "Peace, peace." The soldiers repulsed him, crying out "No peace;" but he nevertheless addressed himself to the Mareschal de Schomberg, who accepted the treaty, and caused his troops to lay down their arms. This peace was confirmed the following year by the treaty of Cherasco, which was negotiated by Mazarin. About the same time he secured to France the town of Pignerol, and deceived both the Spaniards and imperialists, who had only evacuated Casal and Mantua on condition that the French garrison should quit Pignerol. Such conduct excited against him all the hatred of the Spaniards; but it earned for him the acknowledgements of Louis XIII. and of Richelieu, who commended him favourably to the pope. Through the influence of Richelieu he was sent in 1634 to the court of France, in the capacity of nuncio extraordinary. The object of this mission was to intercede in favour of the Duke of Lorraine, who had been deprived of his estates by Louis XIII.

In 1635 the Spaniards, by their intrigues with the sovereign pontiff, procured his recall to Avignon, and even attempted to get his vice-legation revoked; but he anticipated them, and demanding his immediate recall, he in 1636 returned to Rome, where he openly supported the interests of France. He was sent to Savoy by Louis XIII. during the troubles of 1640, with the title of ambassador extraordinary. The successes of the Compte d'Harcourt in Piedmont enabled him, in December 1641, to conclude a treaty between the Duchess of Savoy and her brothers-in-law, who, supported by Spain, had disputed with her the guardianship of her son. It was then that Mazarin obtained the cardinal's hat long since demanded for him by his friend Richelieu. He was included in the nomination of the 16th December 1641, and on the 25th of February 1642 he received the cap from the hands of Louis XIII. The intrigues which had pursued Richelieu during his whole life assumed fresh force towards its close, and on his death-bed he recommended Mazarin warmly to the king, who entrusted him with the direction of all affairs of state. Richelieu had governed by terror; but Mazarin preferred to make himself friends. He obtained the release of Marshal de Bassompierre, Marshal de Vitry, and many other victims of the last minister, recalled several exiled members of parliament, and contributed to the reconciliation of the Duc d'Orleans with the king.

On the death of Louis XIII. on the 14th of May 1643, the administration of affairs was placed entirely in the hands of Mazarin. The commencement of his sway was attended with the happiest success; and the advantages gained by the king's armies secured to the cardinal the applause of the nation. But these favourable dispositions were soon succeeded by the murmurs, not loud but deep, of an oppressed people, and also by a combination of the high nobility who were jealous of his advancement and power. The civil wars of 1649, 1650, 1651, and 1652, followed; his dismissal was at length insisted on, and Mazarin immediately withdrew from the kingdom. Decree upon decree was fulminated against him; his fine library was sold; and a price was even put upon his head; yet, in spite of all the rage of his enemies, he was enabled to return to court with greater power than ever; and many who had formerly been his bitterest enemies now became his warmest friends. He put an end to the war between France and Spain, and, in order to consolidate the peace he had re-established, negotiated a marriage between the king and the infanta, which was celebrated at Saint-Jean-de-Luz on the 9th of June 1660. He died at Vincennes on the 9th of March 1661, in the fifty-ninth year of his age. Mazarin was but little regretted. A courtier writing at the time, says, "Le roi est, ou paraît, le seul touché de la mort du cardinal." He had accumulated immense wealth by very doubtful or equivocal means. His fortune is said to have amounted to near eight millions sterling, all acquired in a period of external war or of internal commotion. On the approach of death he felt some scruples of conscience on the subject, which were, however, soon got over.

The only productions of Mazarin which have been published are his letters. Of these, thirty-six, written by him whilst negotiating the peace of the Pyrenees, made their appearance in the year 1690; and seventy-seven more on the same subject were published in 1693. The whole were collected and reprinted at Amsterdam, in two volumes, under the title of *Negociations Secrètes des Pyrénées*. Abbé Allainval afterwards arranged these letters in chronological order, and, together with fifty unpublished letters, brought them out under the title of *Lettres du Cardinal Mazarin, où l'on voit le Secret de la Négociation de la Paix des Pyrénées*, Paris, 1745, in two vols. 12mo.

The character of Mazarin, who was a thorough Italian in diplomacy, has been compared, or rather contrasted with that of Richelieu, and variously shaded according to the opinions and predilections of those by whom it is delineated. "Cardinal Mazarin," says Hénault, "was as gentle as Cardinal Richelieu was violent; one of his greatest talents consisted in knowing men thoroughly. The character of his policy was rather finesse and prudence than force. He thought that force should never be employed but in default of other means; and his mind supplied the courage required by circumstances; bold at Casale, tranquil and active in his retreat at Cologne; enterprising when it was necessary to cause the princes to be arrested, but insensible to the pleasures of the Fronde; despising the bravadoes of the coadjutor, De Retz, and listening to the murmurs of the people as one listens on the shore to the noise of the waves of the sea. There was in Cardinal Richelieu something greater, vaster, and less composed; in Cardinal Mazarin, more address, more management, and fewer extravagances. People hated the one and derided the other; but both were masters of the state."