Kotor (kôˈtôr) [key], Ital. Cattaro, city (2011 pop. 22,601), SE Montenegro, on the Bay of Kotor, an inlet of the Adriatic. It is a seaport and a tourist center. The town was colonized by Greeks (3d cent. B.C.) and later belonged to the Roman and Byzantine empires. In 1797 it passed to Austria and became an important naval base; in 1918 it was transferred to Yugoslavia and was included in the constituent republic of Montenegro after World War II. It has a medieval fort and town walls and a 16th-century cathedral. As the oldest town in Montenegro, it is a state-protected historical monument.