Year 398 (CCCXCVIII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Eutychianus (or, less frequently, year 1151 Ab urbe condita). The denomination 398 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.

Year 398 (CCCXCVIII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Eutychianus (or, less frequently, year 1151 Ab urbe condita). The denomination 398 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.