The archaeological excavations between 1971 and 1985 by L. Langouët at the foot of the promontory of Alet, ancient settlement previous to the modern town of Saint-Malo, helped to locate the Roman port of Reginca which is mentioned at the 'Peutinger Map', a medieval copy of an ancient road document.

Located at the junction of several river and sea routes, the site of Reginca occupies a prominent place in the Normand-Breton Gulf, which is extended by the Rance and stands as a major traffic artery to penetrate far into the inland region.

The artefacts found during the excavation, show diverse and sometimes remote origins which attest commercial activities throughout antiquity.

 Excavations at Solidor cove delivered the remains of watering installations, one located at the bastion and several of them underwater at the Rance. Those findings helped to draw a very different ancient topography compared to the modern one.