Tartus (tärtōsˈ) [key], town (1995 est. pop. 130,000), W Syria, a port on the Mediterranean Sea. Olive oil is pressed, and petroleum, phosphates, fish, and agricultural produce are shipped. The town is the terminus of an Iraqi oil pipeline. Tartus occupies the ancient site of Antaradus. In A.D. 346 it was rebuilt by Constantine and came to be known, for a time, as Constantia. The town was in Byzantine hands from 968 until 1099, when it was occupied by Crusaders, who also held the town from 1102 to 1291 and renamed it Tartosa. It became famous for the manufacture of camlets, heavy cloths made from camel or goat hair. In 1183 the Knights Templars moved there and fortified the harbor. Tartus is the site of the earliest chapel dedicated to Mary; a cathedral was built around the chapel in the 12th–13th cent.