"the Gray Man placed his hands in the pockets of his dark gray slacks and said, 'Where has gone the steed? Where has gone the youth? Where has gone the giver of treasure? Where are the feasting seats, where the revelry in the hall? Alas, bright goblet; alas, mailed warrior; alas, prince's glory! How that time has passed away, obscured beneath the crown of night as if it never were.'" (The Dream Thieves pg. 109)
This is just one passage of a poem called 'The Wanderer,' which is long and I don't wanna read it cause I don't really fw poetry but apparently the poem is about "the meditations of a solitary exile on his past happiness as a member of his lord's band of retainers, his present hardships and the values of forbearance and faith in the heavenly Lord." I think this passage alone has some very neat parallels to the book - the missing giver of treasure akin to Glendower and his favors, the bright goblet, as cups often are, probably a reference to Blue. What this poem laments as lost is very much the present the kids are living in even as they seek out pieces of this bygone time.