First record, Carsicis Portus, from the Itinerary of Antonin (Roman); 1323: Castrum Cassitis
Prehistoric: Regional habitation is now known to date back 27,000 years, with recent discovery of the underwater Cosquer caves, in the calanques between Cassis and Marseilles. Paleolithic stamped pottery shards and Paleo-Christian lamps were discovered at the Calanque Port-Miou.
Celto-Ligurian: Cassis was a Gallo-Roman fishing port, and numerous Gallo-Roman artifacts have been discovered.
Medieval: Rule changed several times. In the 14th century it belonged to the Seigneurie de Roquefort. In 1376, Pope Gregory XI of Avignon was on his way to restore the Papacy to Rome when his fleet took refuge from a storm in the calanque Port-Miou.In 1443, Cassis became a parish independent from Roquefort, and was ruled by the bishops of Marseille during the end of the 15th century. In the middle of the 16th century, Charles-Quinte of Spain, in the Provencal part of his quest to become Universal Monarch, captured the chateau and pillaged Cassis. The population suffered severely from the great plague of 1720. Except for occasional visits by pirates, which had been happening off and on throughout history, Cassis was relatively calm until 1813 when the English overpowered Napoleon’s defenses and pillaged the port.