The Magic of the Past Is Reworked For Each Age
The Lady of the Lake drew out Excalibur and placed it in Arthur’s hand. The past is a lake from which we draw resources, which come to exist as part of our present. But things have power not just because they derive from a past, but mainly because they can help with contemporary problems, whether these are to do with identity, our connection to the cosmos or more everyday, practical issues. The magic of the past is reworked for each age, and dies only when it has no present use.
— Magic: A History, pp. 237-38