When he was stationed at Paris, the other Doctors of the Sorbonne put before him a problem about the nature of the mystical change in the elements of the Blessed Sacrament, and he proceeded to write, in his customary manner, a very careful and elaborately lucid statement of his own solution. Needless to say, he felt with hearty simplicity the heavy responsibility and gravity of such a judicial decision; and not unnaturally seems to have worried about it more than he commonly did over his work. He sought for guidance in more than usually prolonged prayer and intercession; and finally, with one of those few but striking bodily gestures that mark the turning points of his life, he threw down his thesis at the foot of the crucifix on the altar, and left it lying there; as if awaiting judgment. Then he turned and came down the altar steps and buried himself once more in prayer; but the other Friars, it is said, were watching; and well they might be. For they declared afterwards that the figure of Christ had come down from the cross before their mortal eyes; and stood upon the scroll, saying "Thomas, thou has written well concerning the Sacrament of My Body." It was after this vision that the incident is said to have happened, of his being borne up miraculously in mid-air.

Saint Thomas Aquinas: "The Dumb Ox"
G. K. Chesterton