<p>Remnants of a marble arch with an inscription (<i>CIL</i> VI 878) recording that Augustus rebuilt it (<i>refecit</i>) as Pontifex Maximus, thus after his appointment in 12 B.C., were found in the 14th c. at the piazza in front of the Ponte S. Maria, the ancient *Pons Aemilius (Coarelli 50-51; Richardson; Palombi 262). Most consider it an Augustan monumentalization of the *Porta Flumentana (Coarelli 52; Palombi 263; cf. *Porta Trigemina; *“Arcus Dolabellae et Silani”). Whether the two identical bases of Gaius and Lucius Caesar found near the Temple of *Portunus can be attributed to the Augustan arch flanking it, as Coarelli (51) suggested, remains open (for the bases, s.v. Portunus, Aedes). Our map shows an index number for the “Fornix Augusti” spanning the street from the Pons Aemilius, and accepts the location of this arch as identical with the (more vaguely attested site of the) Porta Flumentana.</p>