Mythopoeia (Greek, "mythos-making") is the title of a poem by J.R.R. Tolkien, and the name of a term coined by him.
"Mythopoeia" was created as reaction to C.S. Lewis' statement that myths were "lies breathed through silver." The poem takes a position opposed to rationalism and materialism, referring to the creative human author as "the little maker" wielding his "own small golden sceptre" ruling his Sub-creation (understood as genuine Creation within God's primary Creation).
While quoted in "On Fairy-Stories" (1947), and mentioned by Humphrey Carpenter in his J.R.R. Tolkien: A Biography (1977), the poem was first published in its entirety in the 1988 edition of Tree and Leaf.
I will not treat your dusty path and flat,
denoting this and that by this and that,
your world immutable wherein no part
the little maker has with maker's art.
I bow not yet before the Iron Crown,
nor cast my own small golden sceptre down.