Year 173 (CLXXIII) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Severus and Pompeianus (or, less frequently, year 926 Ab urbe condita). The denomination 173 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.