What does 501 mean in Telephone Country Codes?

501

Year 501 (DI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Avienus and Pompeius (or, less frequently, year 1254 Ab urbe condita). The denomination 501 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.

see more »