I am lured by the seeming paradox of the moment of a literal, fleeting rose and the moment of a literal thousand-year yew-tree somehow having equal duration. The contrasting life spans of the rose and of the yew and the temporality of the words 'moment' and 'duration' have me thinking that this is a math problem I cannot possibly work out. Or it is downright religious mysticism. The poet doubles and triples the paradox by saying that moments can be both timeless and history making and by saying, also, that there is no escape from time:
A people without history
Is not redeemed from time, for history is a pattern
Of timeless moments.
It seems that the rose and the yew and their paradoxical comparison are devices leading us to a blunt appreciation of the poet's present circumstance, immortalized in so many disparate nows through us readers (who might, in contrast, be without history and unredeemed):
So, while the light fails
On a winter's afternoon, in a secluded chapel
History is now and England.