Year 104 (CIV) was a leap 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 Suburanus and Marcellus (or, less frequently, year 857 Ab urbe condita). The denomination 104 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.

10000 (ten thousand) is the natural number following 9999 and preceding 10001.