Mid 16th century; earliest use found in Thomas Stapleton (1535–1598), Roman Catholic theologian. From post-classical Latin Agnoitae, plural from Byzantine Greek ἀγνοηταί (occasionally also ἀγνοίται) heretics who denied the omniscience of Christ from ancient Greek ἀγνοεῖν to be ignorant + -ται, plural of -της, suffix forming agent nouns.