In Vergilium Commentarius
Maurus (Marius) Servius Honoratus
AC NAVALI SURGENTES AERE COLUMNAS: Columnas dicit, quae in honore Augusti et Agrippae rostratae constitutae sunt. Augustus victor totius Aegypti, quam Caesar pro parte superaverat, multa de navali certamine sustulit rostra, quibus conflatis quattuor effecit columnas, quae postea a Domitiano in Capitolio sunt locatae, quas hodieque conspicimus: unde ait ' navali surgentes aere columnas.' Nam rostratas Duilius posuit, victis Poenis navali certamine, e quibus unam in rostris, alteram ante circum videmus a parte ianuarum.
And columns rising up with prows of bronze: He means the columns which were set up in honor of Augustus and Agrippa, decorated with the prows of warships. Augustus, the victor over all of Egypt, which Caesar had conquered in part, captured many prows in a naval battle. When these had been gathered together, he made four columns, which later were situated on the Capitolium by Domitian; these we see today, whence he says "columns rising up with prows of bronze." Duilius set up columns decorated with prows, after the Phoenicians were conquered in a naval battle, one of which we see on the rostra, the other in front of the circus on the side by the doors.
Translation by Jane W. Crawford, © 2001.