Most of the ramparts that are among the city’s oldest structures are still standing today. The oldest ones of these date back to the Roman Period, 4th century BC. Xenophon who visited the city in the 4th century BC mentions about the ramparts in his book. The ramparts in Trabzon can be divided into three parts which are Yukarı Hisar (İçkale), Orta and Aşağı Hisar.