The story
From thy + -selves, apparently by analogy with yourselves.
Etymology from Wiktionary, CC BY-SA 4.0.
thyselves
thy·selvesToday it means: Yourselves; a plural of the archaic pronoun thyself. Full definition →
Today it means: Yourselves; a plural of the archaic pronoun thyself. Full definition →
From thy + -selves, apparently by analogy with yourselves.
Etymology from Wiktionary, CC BY-SA 4.0.