<p>The 200-m-long embankment wall retained the E bank of the *Tiber beside the *Forum Bovarium, between the *“Cloaca Circi Maximi” in the S and the *Pons Aemilius in the N. Documented by Lanciani shortly before its destruction in the course of the late-19th c., the massive wall was built of tufa blocks with a core of <i>opus caementicium</i> (2-3 m thick, pres. H 6 m) and formed a strong bridgehead at the Pons Aemilius (see fig. 17; Lanciani, <i>FUR</i> pl. 28; Cressedi). Coarelli (37-38) plausibly connects the building of this embankment wall with the artificial elevation of the terrain in the central Forum Bovarium, an activity dated to the early 2nd c. B.C. based on the ceramic finds in the homogeneous infill (36; tentatively connected with a major building campaign of the 170s B.C. attested by Livy 40.51.4: Colini; cf. *Portus Tiberinus).</p> <p>The solid embankment wall secured the most sensitive zone of the city’s exposure to the Tiber. Here, at the river’s main curve through Rome, its currents and floods hit the left bank at a destructively sharp angle, and it was at this point that the city’s central public areas and fortifications most closely approached the riverside. The retaining wall also protected a naturally low point in the physical topography of the city, where Rome’s two main valleys, the Forum valley and Circus Maximus valley (*Vallis: Forum-Velabrum; *Vallis: Circus Maximus), drained into the Tiber. In addition — an aspect not yet considered — the wall must have played a formidable, if not decisive, rôle in Rome’s much-disputed defense line along the Tiber (*Muri: Forum Bovarium-Tiberis). A broad strip of land, some 50-80 m wide, separated the embankment wall from the Forum Bovarium proper; within this “embankment strip” was the precinct of the Temple of *Portunus (at a notably lower elevation than the Forum) and also the platform of the *Round Temple: Tiberis (at a level above the Forum’s). Together with the viaduct leading to the Pons Aemilius, and the artificial harbor of the *Portus Tiberinus just N of that bridge, the embankment wall and “embankment strip” define a zone of entirely man-made topography dating to the early 2nd-early 1st c. B.C.; these works must still have determined the Augustan appearance of Rome between the Tiber and Forum Bovarium. For the embankments and quays S of this area, s.v. *Emporium; for the embankment walls in the shape of a ship’s prow, at the downstream end of the Tiber island, s.v. *Insula Tiberina.</p>