Probably held the quaestorship by 71, since he was a candidate for the praetorship in the autumn of 63 (Cic. Mur. 57). (Broughton MRR II)
See MRR 2.122. The praenomen and the nomen of the Postumus who was a candidate in 63 for a praetorship in 62, and so was probably quaestor by or before 71, remain unattested. He was also one of the prosecutors of Murena (Cic. Mur. 54, 56, 57a, 69). Münzer in his discussion at RE no. 24 expresses serious doubt that he could be a Curtius (cf. Syme, CPh 50, 1955, 134). Sumner (Orators 144145) considers him a Postumius Albinus, perhaps brother or nephew of Postumia, wife of Servius Sulpicius Rufus, the unsuccessful consular candidate. Shackleton Bailey (Studies 58-59) points out that it requires emendation of the forms of the word Postumius in the Pro Murena in four cases out of five (see above), but is, even so, inclined to identify him with the monetalis C. Postumius (12), whom Crawford would date to 74. See below, on C. Postumius (12) and L.? Postumius (15). (Broughton MRR III)