Researcher-Author A. Zeki Teoman (1912 – 1990) writes the following about Zephyrion in his article titled “Mersin Throughout History” without citing any sources:
“… The Zephyrium remains were discovered during the excavation of the foundations of the Mersin Community Center and Governor's Mansion, which were completed in 1945.
… In a report sent to the French Ministry of Foreign Affairs by the French Consul of Tarsus, Monsieur Jille, he wrote, ‘The city of Mersin, which is being established, is being built on the ruins of the old city of Zefirium. It takes its name from the extensive forest of myrtle trees in and around the place where the city was founded.’” In that article, Zeki Teoman also mentions the remains of a four-eyed arch at the site of the Central Bank.
Prof. Dr. Murat Durukan, who researched the history of ancient cities in Mersin and its surroundings, provides the following information about the location of Zephyrion:
“Zephyrion, whose existence we know from ancient sources and coins, is one of the unfortunate ancient cities that remain under modern settlements and about which very little is known. It is not clear when Zephyrion was founded and at what exact location it should be located. However, an area in Mersin city center and on the coast is accepted as the location of the ancient city of Zephyrion. It is noteworthy that the ground level in the area where the structure used as a cultural center today, the Governor's Mansion, the Orthodox church and the Atatürk Statue are located, about 2 km southeast of Yumuktepe, is a few meters higher than its surroundings.
... Barker (W. W. Barker), who published his notes in 1853, describes Zephyrion as being on a promontory and a hill within sight of Anchiale, and emphasizes that this hill is full of ruins of ancient buildings.” [Lost Cities on the Cilician Coast from Mersin to Tarsus, p. 13]

In honor of Emperor Hadrian's visit to the region, probably between 117 and 118, the city's name was changed from Zephyrion to "Hadrianopolis" (Hadrian's City).
The city, which could not resist the Persian attacks that started in the middle of the 3rd century AD, was tried to be completely destroyed. After this date, no revival was seen in the city of Zephyrion for a while. While Tarsus was the Metropolis in the Christian Period, Zephyrion was also affiliated with the spiritual leadership of the Patriarchate of Antioch as the bishopric of this region. Although it was not a Roman city of Zephyrion in the Middle Ages, it is known as a stopover point; at least as a small village pier / harbor where ships stopped to get clean water.

Source: www.yumuktepe.com — Ancient Cilicia Ports