the upper trajan's wall is the modern name given to a fortification located in the central area of modern moldavia. some scholars consider it to be of roman origin, while others think it was built in the third/fourth century by the germanic greuthungi to defend their borders against the huns. it may also have been called greuthungian wall in later roman accounts, but this is uncertain owing to a single polysemic manuscript occurrence in the works of ammianus marcellinus.