The treatise by the Pseudo-Dionysius "De Mystica Theologia" was translated into Latin in the ninth century, but it had to await the first decades of the thirteenth to receive interpretation and commentary. Thomas Gallus, a member of the Victorine School at Paris, glossed the Latin version of Iohannes Sarracenus in 1233. This new, critical edition and translation are based upon all five manuscripts, two of which are recent discoveries. The commentary by Bishop Grosseteste was made at Lincoln around 1242. It was based upon his new version of the Greek text. Both are published here with a translation.These earliest Latin commentators ventured a full-scale reappropriation of the contents of "The Mystical Theology". They explored the trans-conceptual ecstasy of the individual soul that passes through purification and illumination to union with God by means of an exceptional grace of divine love. Between them they provided the context which not only the later mystical theology of monastery and university but also the actual spiritual experience of countless souls was formed.