I took it here: "Eowyn Fighting Nazgul".
"...I loved that sword, because it was found in the church of St. Catherine, whom I loved."
-- Jehanne of Arc, Trial of Condemnation, February 27, 1431
Eowyn was actually fighting the chief of the Nazgul, the Witch-king of Angmar.
"This fulfilled the prophecy of Glorfindel [an Angel, an Elf], for the Witch-king fell not by 'the hand of man', but by a woman and a hobbit." Mordor and the Dark Lord Sauron are allegorical of hell and satan.
One Ring to rule them all, One Ring to find them,
One Ring to bring them all and in the darkness bind them.
St. Catherine broke her boundage. 
She refused to marry the emperor and was imprisoned; the evil ruler used a special spiked wheel to torture her into submission, but the wheel broke.
She married Christ, and received a holy ring.
