5 BC was a common year starting on Monday or Tuesday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a leap year starting on Saturday of the Proleptic Julian calendar. In the Roman world, it was known as the Year of the Consulship of Augustus and Sulla (or, less frequently, year 749 Ab urbe condita). The denomination 5 BC 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.