Portofino was "Portus Delphini" in Roman times, named for its many dolphins. A dolphin under the castle nods to this. The third-century Itinerarium Maritimum mentions it. Romans and Phoenicians used it as a port, showing its old maritime importance. The 10th-century Church of “Divo Martino” was a big religious gift from Empress Adelaide to San Fruttuoso Abbey monks.

The 1361 Convent of San Girolamo at the Cervara shows deep monastic roots. Portofino's got a rich maritime past, with stories of emperors, crusaders, and Richard the Lionheart's fleets. The 10th-century Castle Brown was key in the 1435 Genoese-Venetian conflict. WWII's Portofino Mount battery complexes were crucial for Genoa's defense.