is first mentioned in B. C. 71, when he served as legate under M. Crassus, in the Servile war. (Frontin. Strat. 2.4.8.) He was praetor B. C. 63, in which year he rendered important service to Cicero in the suppression of the Catilinarian conspiracy, especially by the apprehension of the ambassadors of the Allobroges. He afterwards obtained the province of Gallia Narbonensis, and in B. C. 61 defeated the Allobroges, who had invaded the province. In consequence of this victory he sued for a triumph on his return to Rome; but as it was refused by the senate, he remained for some years beyond the pomoerium, urging his claim. At length, in B. C. 54, his friends made a final attempt to procure him the long-desired honour. He was opposed by the praetors, M. Cato and P. Servilius Isauricus, and by the tribune Q. Mucius Scaevola, who urged that he was not entitled to the privilege, because he had not received the imperium by a lex curiata; but he was supported by the consul Appius, and by most of the praetors and tribunes ; and as there was no hope of prevailing upon the senate to grant the favour, his former legate, Serv. Sulpicius Galba, brought the matter before the people, and obtained from them a resolution, passed contrary to law before daylight, in virtue of which Pomnptinus at length entered.the city in triumph. (Sal. Cat. 45; Cic. in Cat. 3.2, de Prov. Cons. 13, in Pison. 14, ad Att. 4.16, 5.1, 4, 5, 6, 8, 10, 14, ad Q. Fr. 3.4.6; D. C. 37.47, 39.65; Liv. Epit. 103.)

In B. C. 51 Pomptinus accompanied Cicero as legate to Cilicia, but he did not remain there longer than a year, according to the stipulation he had previously made with Cicero. (Cic. Att. 5.21.9, 6.3, ad Fam. 2.15.4, 3.10.3, 15.4.9.) There is considerable variation in the orthography of the name. We find him called Pomptinius, Pomtinius, Pomtinus and Pontinius, as well as Pomptinus, which seems the preferable form.