What does 409 mean in US Phone Area Codes?

409

Year 409 (CDIX) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Honorius and Theodosius (or, less frequently, year 1162 Ab urbe condita). The denomination 409 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.

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