Caesar Baronius (1538-1607), Italian cardinal and ecclesiastical historian, was born at Sora, and was educated at Veroli and Naples. At Rome he joined the Oratory in 1557 under St Philip Neri (q.v.) and succeeded him as superior in 1593. Clement VIII., whose confessor he was, made him cardinal in 1596 and librarian of the Vatican. At subsequent conclaves he was twice nearly elected pope, but on each occasion was opposed by Spain on account of his work On the Monarchy of Sicily, in which he supported the papal claims against those of the Spanish government. Baronius is best known by his Annales Ecclesiastici, undertaken by the order of St Philip as an answer to the Magdeburg Centuries. After nearly thirty years of lecturing on the history of the Church at the Vallicella and being trained by St Philip as a great man for a great work, he began to write, and produced twelve folios (1588-1607). In the Annales he treats history in strict chronological order and keeps theology in the background. In spite of many errors, especially in Greek history, in which he had to depend upon secondhand information, the work of Baronius stands as an honest attempt to write history, marked with a sincere love of truth.
Sarpi, in urging Casaubon to write against Baronius, warns him never to charge or suspect him of bad faith, for no one who knew him could accuse him of disloyalty to truth. Baronius makes use of the words of St Augustine: "I shall love with a special love the man who most rigidly and severely corrects my errors." He also undertook a new edition to the Roman martyrology (1586), which he purified of many inaccuracies.
His Annales, which end in 1198, were continued by Rinaldi (9 vols., 1676-1677); by Laderchi (3 vols., 1728-1737); and by Theiner (3 vols., 1856). The most useful edition is that of Mansi (38 vols., Lucca, 1738-1759), giving Pagi's corrections at the foot of each page.