As far as I know, The Cloud of Unknowing was written in the second half of the 14th century. The author is unknown, and its language, Old English, presents difficulties. Its author was well acquainted with Saint Augustine, Pseudo-Dionysius the Areopagite and John Duns Scotus, and in addition to his spiritual interests, had a metaphysical propensity as well as an inclination to apophathic theology.