For valuable citations on the origin and spread of exorcism, see Lecky's European Morals (third English edition), vol.i, pp.

379-385.
Such was the result of a thousand years of theological reasoning, by the strongest minds in Europe, upon data partly given in Scripture and partly inherited from paganism, regarding Satan and his work among men.
Under the guidance of theology, always so severe against "science falsely so called," the world had come a long way indeed from the soothing treatment of the possessed by him who bore among the noblest of his titles that of "The Great Physician." The result was natural: the treatment of the insane fell more and more into the hands of the jailer, the torturer, and the executioner.
To go back for a moment to the beginnings of this unfortunate development.

In spite of the earlier and more kindly tendency in the Church, the Synod of Ancyra, as early as 314 A.D., commanded the expulsion of possessed persons from the Church; the Visigothic Christians whipped them; and Charlemagne, in spite of some good enactments, imprisoned them.

Men and women, whose distempered minds might have been restored to health by gentleness and skill, were driven into hopeless madness by noxious medicines and brutality.

Some few were saved as mere lunatics--they were surrendered to general carelessness, and became simply a prey to ridicule and aimless brutality; but vast numbers were punished as tabernacles of Satan.
One of the least terrible of these punishments, and perhaps the most common of all, was that of scourging demons out of the body of a lunatic.