The Romans were the first invaders of Hersonissos and during their occupation built a large aqueduct as well as an amphitheatre, a harbour and a fountain. The surviving Roman fountain has mosaics depicting fishermen and it is near the east end of the harbour. Remains of the Roman mole of the harbour, one of the best in Crete at this time, are still visible. The Roman quay is on the eastern part of the harbour, partially submerged. On the northeast side of the peninsula cuts in the rock are thought to be Roman fish tanks. In Kastri, on the east side of the peninsula above the church of Agia Paraskevi, was a solidly-built Roman fort.