The works of this period are Les Philosophes Salaries, Machiavel juge des revolutions de notre temps (1849), La Federazione repubblicana (1851), La Filosofia della rivoluzione (1851), L' Italia dopo it colpo di Stato (1852), Histoire des revolutions, ou Guelfes et Gibelins (1858; Italian trans., 1871-1873).
It is not in virtue of his great age alone that this can be said of him; he actually had much in common with the beaux esprits of the 17th century, as well as with the philosophes of the 18th.
Received at first in the ranks of the philosophes, he soon went over to their opponents, possibly more from contempt than from conviction, the immediate occasion for his change being a quarrel with d'Alembert in 1762.
His opposition to 'the philosophes had its strongest expressions in Fanatisme des philosophes (Geneva and Paris, 1764) and Histoire des revolutions de l'empire romain (Paris, 1766-1768).
His great literary power, his reputation for benevolence, and his known toleration and dislike of doctrinal disputes caused him to be much more favourably regarded than most churchmen by the philosophes of the 18th century.