From ancient times; since long ago — indicating a long-standing tradition or state, often used in written language.
古来よりこの地域では祭りが大切にされてきた。
Since ancient times, festivals have been cherished in this region.
その慣習は古来の伝統に基づいている。
That custom is based on an ancient tradition.
古来、植物は薬としても利用されてきた。
Plants have been used as medicine since ancient times.