mists of time

Noun

plural plural-only

Any time so long ago that history is no longer clear, as though lost in a mist or fog.

Japanese Meaning

歴史が曖昧になり、霧に包まれたかのような遥か昔の時代 / 記憶の中で薄れていった、非常に遠い昔 / 伝説や神話のように具体性を失った、あいまいな過去の時期

Legends about the ancient lighthouse have been swallowed by the mists of time, leaving only scattered fragments of truth.

古い灯台にまつわる伝説は時の霧に飲み込まれ、真実の断片だけが散らばって残っている。

Sense（1）

Any time so long ago that history is no longer clear, as though lost in a mist or fog.

lost in the mists of time