7. LIVIUS DRUSUS CLAUDIANUS, the father of Livia, who was the mother of the emperor Tiberius. He was one of the gens Claudia, and was adopted by a Livius Drusus. (Suet. Tib. 3; Vell. Paterc. 2.75.) It was through this adoption that the Drusi became connected with the imperial family. Pighius (Annales, iii. p. 21), by some oversight which is repugnant to dates and the ordinary laws of human mortality, makes him the adopted son of No. 3, and confounds him with No. 5, and, in this error, has been followed by Vaillant. (Num. Ant. Fam. Rom. 2.51.) There is no such inconsistency in the supposition that he was adopted by No. 7, who is spoken of by Suetonius as if he were an ancestor of Tiberius. (Augustinus, Fam. Rom. (Livii) p. 77; Fabretti, Inscr. c. 6, No. 38.) The father of Livia, after the death of Caesar, espoused the cause of Brutus and Cassius, and, after the battle of Philippi, being proscribed by the conquerors, he followed the example of others of his own party, and killed himself in his tent. (Dio Cass 48.44; Vell. Paterc. 2.71.) It is likely that he is the Drusus who, in B. C. 43, encouraged Decimus Brutus in the vain hope that the fourth legion and the legion of Mars, which had fought under Caesar, would go over to the side of his murderers. (Cic. ad Fanm. 11.19.2.)
In other parts of the correspondence of Cicero, the name Drusus occurs several times, and the person intended may be, as Manutius conjectured, identical with the father of Livia. In B. C. 59, it seems that a lucrative legation was intended for a Drusus, who is called, perhaps in allusion to some discreditable occurrence, the Pisaurian. (Ad Att. 2.7.3.) A Drusus, in B. C. 54, was accused by Lucretius of praevaricatio, or corrupt collusion in betraying a cause which he had undertaken to prosecute. Cicero defended Drusus, and he was acquitted by a majority of four. The tribuni aerarii saved him, though the greater part of the senators and equites were against him; for though by the lex Fufia each of the three orders of judices voted separately, it was the majority of single votes, not the majority of majorities, that decided the judgment. (Ad Att. 4.16. §§ 5, 8, ib. 15.9, ad Qu. Fr. 2.16.3. As to the mode of counting votes, see Ascon. in Cic. pro Mil. p. 53, ed. Orelli.) In B. C. 50, M. Caelius Rufus, who was accused of an offence against the Scantinian law, thinks it ridiculous that Drusus, who was then probably praetor, should be appointed to preside at the trial. Upon this ground it has been imagined that there was some stigma of impurity upon the character of Drusus. (Ad Fam. 8.12.3, 14.4.) He possessed gardens, which Cicero was very anxious to purchase. (Ad Att. 12.21.2, 22.3, 23.3, 13.26.1.)