Tartous is a Phoenician city built as an extension of the main settlement in the island of Arwad (Aradus). Its name is derived fron Antaradus or Anti-Aradus. Constantius renamed the city Constantia in 346.

Taken by the Muslims in 630 AD then conquerred by the Byzantines in 968 it came again into Muslims hands under the Fatimid in 997.

Taken by Crusader's Raymond, Count of  Toulouse, the city was fortified and was part of the principality of Tripoli.

In 1123 Crusaders began the construction of the Cathedral Church of Our Lady of Tortosa a fine example of Romanesque.