The rocks had stood overlooking the valley since time immemorial.
Origin of immemorial
Medieval Latin immemoriālis Latin in-notin–1 Latin memoriālismemorialmemorial
The temple of Karnak is no doubt of immemorial antiquity.
Rice has been cultivated from time immemorial in tropical countries.
Such nobility may be immemorial or it may not.
A kind of seigniorial taille continued to exist besides the servile taille, but this kind presupposed a title, a contract between the taxable roturier and the lord, or else immemorial possession, which amounted to a title.
But if differed from the old patriciate in this, that, while the privileges of the old patriciate rested on law, or perhaps rather on immemorial custom, the privileges of the new nobility rested wholly on a sentiment of which men could remember the beginning.