What is the origin of the idiom "time out of mind" and when to use it?

The idiom "time out of mind" has its origins in Middle English and can be traced back to the 15th century. The term "out of mind" in this context does not refer to forgetfulness but rather denotes a time so far in the past that it is beyond the scope or memory of the speaker. The phrase is often used to convey the idea of an ancient or indefinite period, emphasizing the antiquity or timelessness of a situation or condition.