Year 399 (CCCXCIX) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Eutropius and Theodorus (or, less frequently, year 1152 Ab urbe condita). The denomination 399 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.