Their conversion made little change in the attitude of the emperors, and Constantine and his successors continued to exercise a supreme jurisdiction over the hierarchy. The sixteenth book of the Theodosian Code sufficiently sets forth the plenitude of their authority. In theory, bishops were elected by the clergy and the people, but in practice the emperor could control the patronage if it were valuable; and whether bishops were elected or appointed, as long as they were created and paid by laymen, they were dependent. The priesthood could only become autocratic when fear of the miracle exempted them from arrest; and toward the middle of the fifth century this point was approaching, as appears by the effect of the embassy of Leo the Great to Attila.
In 452 the Huns had crossed the Alps and had sacked Aquileia. The Roman army was demoralized; Aëtius could not make head against the barbarians in the field; while Valentinian was so panic-stricken that he abandoned Ravenna, which was thought impregnable, and retreated to the capital, which was indefensible. At Rome, finding himself helpless in an open city, the emperor conceived the idea of invoking the power of the supernatural. He proposed to Leo to visit Attila and persuade him to spare the town. The pope consented without hesitation, and with perfect intrepidity caused himself to be carried to the Hun's tent, where he met with respect not unalloyed by fear. The legend probably reflects pretty accurately the feeling of the time. As the bishop stood before the king, Peter and Paul appeared on either side, menacing Attila with flaming swords; and though this particular form of apparition may be doubted, Attila seems beyond question to have been oppressed by a belief that he would not long survive the capture of Rome. He therefore readily agreed to accept a ransom and evacuate Italy.
From the scientific standpoint the saint and the sorcerer are akin; for though the saint uses the supernatural for man's benefit, and the sorcerer for his hurt, both deal in magic. The mediæval saint was a powerful necromancer. He healed the sick, cast out devils, raised the dead, foretold the future, put out fires, found stolen property, brought rain, saved from shipwreck, routed the enemy, cured headache, was sovereign in child-birth, and, indeed, could do almost anything that was asked of him, whether he were alive or dead. This power was believed to lie in some occult property of the flesh, which passed by contact. The woman in the Bible said, "If I may touch but his clothes, I shall be whole." Moreover, this fluid was a substance whose passage could be felt, for "Jesus, immediately knowing in himself that virtue had gone out of him, turned him about in the press, and said, Who touched my clothes?"[82]