AI overview
I don't have any context provided about "100 BC" beyond the label "year," so I cannot write an accurate overview based on your instruction to use only the provided context. To help you, I would need information about what specific "100 BC" refers to—whether it's a historical period, an event, a book, a film, or something else.
AI-generated from the Wikipedia summary — may contain errors.
Article
Year 100 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Marius and Flaccus (or, less frequently, year 654 Ab urbe condita) and the First Year of Tianhan. The denomination 100 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.
Map of the world in 100 BC