was the son of a wealthy Roman eques of the same name, who appears to have obtained his property as a negotiator in Africa. He was accused of parsimony, especially in reference to his son, but the extravagant habits of the latter required some degree of restraint. He was alive at the trial of his son in B. C. 56 (Cic. pro Cael. 2, 15, 30, 32.) The younger Caelius was born at Puteoli on the 28th of May, B. C. 82. on the same day and the same year as the orator C. Licinius Calvus, in conjunction with whom his name frequently occurs (Plin. Nat. 7.49. s. 50; Quint. Inst. 10.1.115, 10.2.25, 12.10.11). His father was enabled to procure him introductions to M. Crassus and Cicero, who gave him the advantage of their advice in the prosecution of his studies, especially in the cultivation of oratory. During Cicero's praetorship (B. C. 66), and the two following years, Caelius was almost always at his side; but in the consulship of the great orator (B. C. 63), he became intimate with Catiline, whose society had such extraordinary fascinations for all the wealthy Roman youths ; although he took no part in the conspiracy, if we may trust Cicero's positive assurance. In B. C. 61, he accompanied the proconsul Q. Pompeius Rufus to Africa, partly to become acquainted with the mode of administering a province, but probably still more in order to look after his father's property in that country. On his return to Rome he accused in B. C. 59 C. Antonius, Cicero's colleague in the consulship, of having been one of Catiline's conspirators ; and notwithstanding Cicero spoke in his behalf, Antonius was condemned. The oration which Caelius delivered against Antonius possessed considerable merit, and was read in the time of Quintilian (Quint. Inst. 4.2.123, 9.3.58). Not long afterwards he obtained the quaestorship, and was charged with having purchased the votes at his election, an accusation from which Cicero endeavoured to clear him when he defended him in B. C. 56.

In B. C. 57, Caelius accused L. Sempronius Atratinus of bribery, and when the latter, who was defended by Cicero, was acquitted, he accused him again of the same crime in B. C. 56. But while the second suit was in progress, and had not yet come on for trial, Caelius himself was accused of vis by Sempronius Atratinus the younger. Caelius had for some time been living in the house of P. Clodius on the Aventine, and was one of the avowed paramours of his notorious sister Clodia Quadrantaria. He had, however, lately deserted her ; and she, in revenge, induced Sempronius Atratinus to bring him to trial. The two most important charges in the accusation arose from Clodia's own statements; she charged him in the first place with having borrowed money from her in order to murder Dion, the head of the embassy sent by Ptolemy Auletes to Rome; and declared, in the second place, that he had made an attempt to carry her off by poison. Caelius spoke on his own behalf, and was also defended by M. Crassus and Cicero : the speech of the latter is still extant. Caelius had done great damage to his character, not only by his intrigue with Clodia, but still more by the open part he had taken both at Baiae as well as at Rome in the extravagant debaucheries of herself and her friends; and Cicero therefore exerts himself to show that the reports respecting the character of his client were unfounded, or at least grossly exaggerated; that he was not the extravagant spendthrift and luxurious debauchee that he had been represented, but had devoted much of his time to serious occupations, especially to the study of oratory. The judges acquitted him ; and a second accusation, which the Claudii brought against him two years afterwards (Cic. ad Q. Fr. ii 13), appears likewise to have failed.

In B. C. 52, Caelius was tribune of the plebs. He warmly supported Milo, who murdered P. Clodius at the beginning of this year, and he opposed the measures brought forward by Pompey. But his efforts were all in vain, and Milo was condemned. (Comp. Cic. pro Mil. 33.) In the same year he proposed a bill in conjunction with his nine colleagues to allow Caesar to become a candidate for a second consulship in his absence. To this measure no serious opposition was offered as Pompey did not venture to refuse to it his sanction. No sooner had his year of office expired than he accused his late colleague Q. Ponipeius Rufus of vis under the provisions of the very law which the latter had taken so active a part in passing. The triumvir, who had no further occasion for his services, rendered him but faint support. He was condemned, and retired to Bauli in Campania, where he was in great pecuniary difficulties, till Caelius generously compelled Cornelia, the mother of Pompeius, to surrender to him his paternal property. (V. Max. 4.2.7.)

In B. C. 51, Cicero went to Cilicia as proconsul, much against his will, and before leaving Italy he requested Caelius, who accompanied him on his journey as far as Cumae, to send him from time to time a detailed account of all the news of the city. Caelius readily complied with his request, and his correspondence with his friend is still preserved in the collection of Cicero's letters. In the same year Caelius became a candidate for the curule aedileship, which he gained along with Octavius. As he was anxious to exhibit the games with becoming splendour, he applied to Cicero for money and for panthers, as his command of an Asiatic province would enable him to obtain a large supply of both without much difficulty. Cicero, with all his faults, did not plunder the provincials. He therefore refused the money at once ; and does not seem to have put himself to much trouble to procure the panthers, although Caelius reminds him of them in almost every letter. During his aedileship in the following year (B. C. 50), Caelius still carried on his correspondence with Cicero; and his letters contain some interesting ing accounts of the proceedings of the different parties at Rome immediately before the breaking out of the civil war. In the same year he became involved in a personal quarrel with the censor Ap. Claudius Pulcher, and with L. Domitius Ahenobarbus. who had been the colleague of Claudius in the consulship; but we must refer the reader for particulars to his correspondence with Cicero (Cic. Fam. 8.12, 14). Having thus become a personal sonal enemy of two of the most distinguished leaders of the aristocracy, his connection with this party, of which he had hitherto been a warm supporter, was naturally weakened. He felt no confidence in Pompey and the senate in the impending pending civil war; he saw that Caesar was the stronger; and avowing the principle that the more powerful party is to be joined when the struggle in a state comes to arms, he resolved to espouse the side of Caesar.

In the discussions in the senate at the beginning of January, B. C. 49, Caelius supported the opinion of M. Calidius that Pompey ought to betake himself to his Spanish provinces in order to remove every pretext for war. By this declaration he openly broke with the aristocratical party, and in a few days afterwards he fled from Rome with M. Antonius, Q. Cassius, and C. Curio to Caesar's camp at Ravenna (Caes. Civ. 1.2; D. C. 41.2, 3). Caesar sent him into Liguria to suppress an insurrection at Intemelium (ad Fam. 8.15); and in April he accompanied Caesar in his campaign in Spain (ad Fam. 8.16.4,17.1). It is supposed by some modern writers that he also served under Curio in Africa in the course of the same year, as we read of a M. Rufus who was the quaestor of Curio in Africa (Caes. Civ. 2.43); but this M. Rufus must in all probability have been a different person.

He was rewarded for his services by the praetorship, which he held in B. C. 48. But various causes had already alienated the mind of Caelius from his new patron, and these at length led him to engage in desperate enterprises which ended in his ruin and death. He was mortified that Caesar had entrusted the honourable duties of the city praetorship to C. Trebonius rather than to himself, a distinction, however, to which Trebonius had much greater claims, as he had in his tribuneship in B. C. 55 proposed the law for prolonging the proconsular government of Caesar. But his chief dissatisfaction with the existing state of things arose from his enormous debts. It seems that he had looked forward to a proscription for the payment of his creditors; but as Caesar's generous conduct towards his opponents deprived him of this resource, he saw no remedy for his ruined fortunes but a general commotion. Accordingly, when Trehonius was, in the exercise of his judicial duties, carrying into execution the law which had been lately passed by Caesar for the settlement of debts, Caelius set up his tribunal by the side of his colleague and promised his assistance to all who might appeal to him against the decision of the latter. But as no one availed himself oi his proffered. aid, he brought forward a law according to which debts were to be paid without interest in six instalments, probably at the interval of six months from one another. *The passage in Caesar (Caes. Civ. 3.20), from which the statement in the text is taken, is corrupt :--"legemr promulgavit, ut series seni dis sine usuris creditae pecuniae solvantur." Niebuhr conjectures series semestri die (Kleine Schriften, vol. ii. pp. 253, 254.) When this measure was opposed by Servilius Isauricus, Caesar's colleague in the consulship, and by the other magistrates, he dropt it and brought forward two others in its place, which were in fact equivalent to a general confiscation of property. By one of these new laws the proprietors of houses had to give up a year's rent to their tenants, and by another creditors were to forgive debtors all their debts. After such sweeping measures as these, the decisions of Trebonius, however lenient, would seem harsh towards wards debtors. A mob attacked him as he was administering justice; several persons were wounded, and Trebonius himself driven from his tribunal. Thereupon the senate resolved to deprive Caelius of his office, and Servilius carried the decree into execution by breaking himself the curule seat of the praetor. Caelius saw that he could effect nothing more at Rome, and accordingly left the city, giving out that he intended to repair to Caesar. But his real intention was to join Milo in Campania. whom he had secretly sent for from Massilia, and along with him to raise an insurrection in favour of Pompey. Milo, however, was killed in an attack upon an obscure fort near Thurii before Caelius could join him [MILO] ; and Caelius himself was put to death shortly afterwards at Thurii by some Spanish and Gallic horsemen who he was endeavouring to bribe to surrender render the place. (Caes. Civ. 3.20-22; D. C. 42.22_25; Appian, App. BC 2.22; Liv. Epit. Ill; Vell. 2.68; Oros. 6.15; Quint. Inst. 6.3.25.)