A google search on '"Osip Mandelstam" "gene wolfe" dwindle' produces no hits, and this post is intended to rectify this.
Osip Mandelstam was a poet in Russia, but his later poetry didn't please Stalin, and he spent his later years in exile, serving sentences for counter-revolutionary activities in various work camps, until his death on December 27, 1938, in the Gulag Archipelago. I only know of him because of the fragment that starts "The Sword of the Lictor" by Gene Wolfe:
Into the distance disappear the mounds of human heads.
I dwindle - go unnoticed now.
But in affectionate books, in childrens' games,
I will rise from the dead to say: the sun!
Now I look for the source, I find that the "official" translation is:
Mounds of human heads are wandering into the distance.
I dwindle among them. Nobody sees me. But in books
much loved, and in children's games I shall rise
from the dead to say the sun is shining.
I prefer the Wolfe version (is it his own version? I don't know). I would also omit "from the dead" from the last line, and perhaps change rise to arise, if I was writing my own book. Since Osip Mandelstam is a bit of an odd name, and the poem distinctly odd, I had wondered if it was an invented quote, with no convenient way to find out. But now google will tell me in seconds.
Book 1 starts with A thousand ages in thy sight/Are like an evening gone./Short as the watch that ends the night/Before the rising sun - which is a hymn based on Psalms 90.
Book 2 with But strength still goes out from your thorns,/and from your abysses the sound of music. / Your shadows lie on my heart like roses / and your nights are like strong wine, which appears to be a GW original and I think you can tell [*].
Book 4 is AT two o'clock in the morning, if you open your window and listen, / You will hear the feet of the Wind that is going to call the sun. / And the trees in the shadow rustle and the trees in the moonlight glisten, / And though it is deep, dark night, you feel that the night is done, which is Kipling.
TUotNS (which I found rather disappointing) is "Awake, for morning in the bowl of night..." by Fitzgerald; my father used to quote that a lot.
[*] Ha, I'm wrong. But I'm correct that its weird. Its actually Gertrud von Le Fort; see for example google books. "Thorns" is then the obvious Christ reference; but "Your shadows lie on my heart like roses" is beautiful. Thanks to JY.