AI overview
I can't write an accurate overview of "400" based only on "year" as context, since this single word doesn't tell me whether you're referring to a historical year (like 400 AD), a book, a film, a scientific measurement, a sports record, or something else entirely. Could you provide more context about what "400" refers to?
AI-generated from the Wikipedia summary — may contain errors.
Article
The Eastern Hemisphere in 400 Europe in 400
Year 400 (CD) was a leap year starting on Sunday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Stilicho and Aurelianus (or, less frequently, year 1153 Ab urbe condita). The denomination 400 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. It was the 400th year of the Common Era (CE) and Anno Domini (AD) designations, the 400th year of the 1st millennium, the 100th and last year of the 4th century, and the 1st year of the 400s decade.