Because of the fear of an imminent French invasion, he left Naples on 29 October 1557, and traveled to Rome, where he continued his legal studies and obtained a doctorate in utroque iure in 1561.

Baronio was soon drawn to the circle of Philip Neri, who opened a meeting place for churchmen and laity who were interested in intellectual discussions on religion and philosophy.

After repeated commands from Neri, however, Baronius changed his mind and spent the rest of his life devoted to this enormous task.

[9] In the Annales, Baronio coined the term "Dark Age" in the Latin form saeculum obscurum,[10] to refer to the period between the end of the Carolingian Empire in 888 and the first inklings of the Gregorian Reform under Pope Clement II in 1046.

Notwithstanding its errors, especially in Greek history where he was obliged to depend upon secondhand information, Baronio's work stands as an honest attempt at historiography.

Sarpi, in urging Casaubon to write a refutation of the Annales, warned him never to accuse or suspect Baronio of bad faith.

[5] Baronio also undertook a new edition of the Roman Martyrology (1586), in the course of his work he applied critical considerations to removed entries he considered implausible for historical reasons, and added or corrected others according to what he found in the sources to which he had access.

"[11] This remark, which probably Baronio (according to some) made in conversation with Galileo, before the controversy, as he died before it, was cited by the latter (without precise attribution) in his Letter to the Grand Duchess Christina (1615).

[13] A Latin biography of Baronio by the oratorian Hieronymus Barnabeus (Girolamo Barnabeo or Barnabò) appeared in 1651 as Vita Caesaris Baronii.

[15] There are other biographies by Amabel Kerr (1898),[16] and by Generoso Calenzio (La vita e gli scritti del cardinale Cesare Baronio, Rome 1907).