since time immemorial

US /sɪns taɪm ɪmɪˈmɔːriəl/
UK /sɪns taɪm ɪmɪˈmɔːriəl/
"since time immemorial" picture
1.

有史以来, 遠い昔から

for a very long time, for a period longer than anyone can remember

:
The tradition has been passed down since time immemorial.
その伝統は有史以来受け継がれてきた。
People have been fishing in this river since time immemorial.
人々は有史以来この川で魚を捕ってきた。