<p>The Arch of Dolabella and Silanus, a single bay travertine arch (W. 4 m, H. 6.56 m), stands on the summit of the *Caelian at the upper end of the *“Clivus Scauri” close to the present-day Church of S. Maria in Domnica. The arch is decorated with two plain cornices, and on its E attic façade an inscription dates it to A.D. 10 and indicates that it was built by the consuls P. Cornelius Dolabella and C. Iunius Silanus: P. CORNELIVS P.F. DOLABELLA C. IVNIVS C.F. SILANVS FLAMEN MARTIAL(IS) CO(N)S(VLES) EX S.C. FACIVNDVM CVRAVERVNT IDEMQVE PROBAVERVNT (<i>CIL</i> VI 1384; Richardson 25; Mari 91).</p> <p>Formerly the arch was thought to have been part of the *Aqua Marcia (Mari 91). Now, Colini’s hypothesis that the arch replaced the <i>porta Caelimontana</i>, one of the two known Caelian gates in the *Servian Wall, is widely accepted (Colini 33-34; Coarelli, <i>LTUR</i>; Richardson; Säflund; cf. *Porta Querquetulana). Colini observed that blocks of Grotta Oscura tufa, typical of the Servian Wall, were connected to the N pier of the Arch of Dolabella and Silanus, and suggested that in A.D. 10 this arch replaced the <i>porta Caelimontana</i>, which, following Livy 35.9.2-3, stood on the summit of the Caelian (Colini 35, Mari 91). Thus, the *“Via Caelimontana” would have passed through the Servian Wall here, to continue within the city as the “Clivus Scauri”.</p> <p>An inscription of A.D. 2 with the same formula and content as that of the Arch of Dolabella and Silanus marked the *“Arcus Lentuli et Crispini”. The similarity of these two monuments may indicate an Augustan-era renovation of the Servian Gates from the *Tiber to the Caelian (Coarelli 1988). Under Nero, the Arch of Dolabella and Silanus was incorporated into the <i>aqua Claudia</i>.</p>