Separated from Lycabettus by a depression to the south-west, through which flows a brook, now a covered drain (probably to be identified with the Eridanus), stands the remarkable oblong rocky mass of the Acropolis (512 ft.), rising precipitously on all sides except the western; its summit was partially levelled in prehistoric times, and the flat area was subsequently enlarged by further cutting and by means of retaining walls.
The Dipylon consists of an outer and an inner gate separated by an oblong courtyard and flanked on either side by towers; the gates were themselves double, being each composed of two apertures intended for the incoming and outgoing traffic. An opening in the city wall a little to the south-west, supposed to have been the Sacred Gate (iep t riAn), was in all probability an outlet for the waters of the Eridanus.
Next they sailed up the Eridanus into the Rhodanus, passing through the country of the Celts and Ligurians to the Stoechades, then to the island of Aethalia (Elba), finally reaching the Tyrrhenian Sea and the island of Circe, who absolved them from the murder of Absyrtus.
Although he was at least sixty-five years of age at this period, his poetic faculty displayed itself with more than usual warmth and lustre in the glowing series of elegies, styled Eridanus, which he poured forth to commemorate the rapture of this union.
His most original compositions in verse, however, are elegiac and hendecasyllabic pieces on personal topics - the De conjugali amore, Eridanus, Tumuli, Naeniae, Baiae, &c. - in which he uttered his vehemently passionate emotions with a warmth of southern colouring, an evident sincerity, and a truth of painting from reality which excuse their erotic freedom.