CAELIUS (MARCUS CAELIUS RUFUS) (82?-48 B.C.), Roman politician, was born at Puteoli on May 28, B.C. 82, the son of a Roman eques of the same name. (But see Nipperdey, Rheinisches Museum, xix., 29o.) He was educated under the instructions of Crassus and Cicero, and was constantly with Cicero during Cicero's praetorship (66) and subsequently. In 63 he became intimate with Catiline, but according to Cicero was not involved in the conspiracy. In 61 he went to Africa as comes to the pro consul Q. Pompeius Rufus, and on his return in S9 successfully accused C. Antonius, who had been consul with Cicero, of com plicity in the Catilinarian conspiracy, in a brilliantly savage speech which still survived in Quintilian's day (Quint. IV., ii., 123, and IX., iii., 58) . About that time he was quaestor.
In 56 he was accused of violence (vis), at the instance of Clodia, who had been his mistress, and whom he had deserted and saddled with the nickname quadrantaria Clytaemnestra. Caelius is probably the Rufus whom Catullus accuses of stealing Clodia from him. Caelius spoke in his own defence and Crassus and Cicero also spoke for him. He was acquitted. In 52 he was tribune and opposed Pompey's measures for bringing Milo to trial. He was induced by Pompey, against his own judgment, not to veto the law of the ten tribunes, allowing Caesar to stand for the consulship in absence.
In 51 Cicero went to Cilicia as proconsul, and Caelius kept him supplied with news from Rome. His letters are preserved in the collection of Cicero's correspondence. One in particular (Ad Pam. viii.) gives a vivid account of the proceedings in the senate on the motion of Marcellus to deal with the consular provinces. In 5o he was aedile, and his letters to Cicero are dotted with requests for panthers for his games. About this time he became a supporter of Caesar. In Ad Pam. viii. 14, written to Cicero in Aug. 5o, he foresees civil war and seems reluctantly determined to join Caesar. In 49 he supported the motion that Pompey should leave for Spain, and immediately afterwards fled to Caesar's camp at Ravenna. Later that year he fought for Caesar in Liguria and Spain. In 48 he was made praetor peregrinus, and Caesar left for the war with Pompey. Indignant at being passed over for the urban praetorship in favour of Tre bonius, and disappointed in his hopes of a proscription, which would have enabled him to pay his debts, he set up a tribunal as a counter-attraction to Trebonius, who was administering Caesar's scheme for payment of debts, and introduced measures amount ing to a general cancellation of debts. The senate deprived him of his office, and he left Rome to join Milo in Campania. The two of them got up a revolt and were both killed, Caelius at Thurii, by some provincial cavalry whom he was trying to bribe. Brilliant and cynical, capable of impetuous acts of kindness or savagery, he captured the imagination of antiquity, and most authorities have a good word for him. He lives more vividly than most of the men of his age, in his letters to Cicero.
See Cicero, Pro Caelio, Epp. ad. Fain.; the Introduction to Tyrrell and Purser's Correspondence of Cicero (Dublin, 1896), vol. iii.; for his style see F. Becher, Ueber den Sprachgebrauch des Caelius (Ufeld, i888).