Ancient history
01
古代史, 古代世界の歴史
a history of the ancient world
02
古代史, 昔の話
knowledge of some recent fact or event that has become so commonly known that it has lost its original pertinence
03
古代史, 遠い過去
something that occurred a long time ago and is now considered irrelevant or unimportant
Informal
例
That argument we had is ancient history, so let's not bring it up again.
私たちがしたあの議論は過去の話ですから、もう持ち出さないようにしましょう。
His past mistakes are ancient history now that he ’s completely changed his ways.
彼の過去の過ちは、彼が完全にやり方を変えた今では古代史です。
