8. Q.ServiliusCaepio, quaestor urbanus in B. C. 100. He may have been the son of No. 7, but as the latter in all probability obtained the consulship at the usual age, it is not likely that he had a son old enough to obtain the quaestorship six years afterwards. In his quaestorship Caepio opposed the lex frumentaria of the tribune L. Saturninus, and when Saturninus insisted upon putting the law to the vote, notwithstanding the veto of his colleagues, Caepio interrupted the voting by force of arms, and thus prevented the law from being carried. He was accused in consequence of treason (majeslas), and it was perhaps upon this occasion that T. Betucius Barrus spoke against him. The oration of Caepio in reply was written for him by L. Aelius Praeconinus Stilo, who composed orations for him as well as for other distinguished Romans at that time. (Auct. ad Herenn. 1.12; Cic. Brut. 46, 56.)

In the contests of the year B. C. 91, Caepio deserted the cause of the senate and espoused that of the equites in opposition to the lex judiciaria of the tribune M. Livius Drusus, who proposed to divide the judicia between the senate and the equites. Caepio and Drusus had formerly been very intimate friends, and had exchanged marriages, by which we are to understand, that Caepio had married a sister of Drusus and Drusus a sister of Caepio, and not that they had exchanged wives, as some modern writers would interpret it. The enmity between the brothers-in-law is said to have arisen from competition in bidding for a ring at a public auction (Plin. Nat. 33.1. s. 6), but whatever may have been its origin, it was now of a most determined and violent character. The city was torn asunder by their contentions, and seemed almost to be divided between two hostile armies. To strike terror into the senate, Caepio accused two of the most distinguished leaders of the body, M. Aemilius Scaurus of extortion (repetundae), and L. Marcius Philippus, the consul, of bribery (amnbitus). Both accusations, however, seem to have failed, and Scaurus, before his trial came on, retaliated by accusing Caepio himself. (Dio Cass. Frag. cix. cx. p. 45 ; Flor. 3.17; Plin. Nat. 28.9. s. 41; Cic. pro Dom. 46, Brut. 62, pro Scaur. 1; Ascon. in Scaur. p. 21, ed. Orelli.) The assassination of Drusus shortly afterwards was supposed by some to have been committed at the instigation of Caepio. (Aurel. Vict. de Vir. Ill. 66.)

On the breaking out of the social war in the following year, B. C. 90, Caepio again accused his old enemy Scaurus under the provisions of the Varia lex, which had been passed to bring all to trial who had been instrumental in causing the revolt of the allies. (Cic. pro Scaur. 1; Ascon. in Scaur. p. 22.) Caepio took an active part in this war, in which he served as the legate of the consul P. Rutilius Lupus, and upon the death of the latter he received, in conjunction with C. Marius, the command of the consular army. Caepio at first gained some success, but was afterwards decoyed into an ambush by Pompaedius, the leader of the enemy's army, who had pretended to revolt to him, and he lost his life in consequence. (B. C. 90.) (Appian, App. BC 1.40, 44; Liv. Epit. 73.)