BC; BCE; before the Common Era
Used to indicate years before the start of the Gregorian calendar. Often placed after a year number, e.g., 500紀元前 (500 BC).
This temple was built in 500 BC.
その出来事は紀元前にさかのぼる。
The event dates back to before the Common Era.
This city was built in 500 BC.
I studied a philosopher from the 5th century BC.