Year 409 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Cossus and Medullinus (or, less frequently, year 345 Ab urbe condita). The denomination 409 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.
Read more about 409 BC: Deaths