The temple and its associated buildings stood at an elevation of three hundred feet above the sea-level and at a distance of a little more than two miles from the city of Cos. The heights behind the temple were in former times covered with forests and afforded ample protection against the debilitating and much-dreaded south wind. A brook of considerable size and of very pure water passed through the temple grounds; the spring (Burinna) from which it took its origin being located about 300 feet higher up on the side of the mountain. Not far off, in the same neighborhood, is a mineral spring, the water from which contains both iron and sulphur. All the physical conditions of this site were, therefore, very favorable to the restoration of both mental and bodily health. Professor Meyer-Steineg declares that it is scarcely possible to determine accurately the age of the Cos Asclepieion,--_i.e._, of the structures which the present ruins represent,--but he believes that some of them date no farther back than the third century B. C., at which time extensive structural alterations were made.[17] Then, at a still later date (first century A. D.), in consequence of the damage done by an earthquake, C. Stertinius Xenophon (at the instigation of the Roman Emperor Claudius, whose private physician he was) carried out some very radical changes. Not only were the separate buildings well supplied with running water, but even many of the individual rooms (of which there were a large number) were equipped with the same conveniences. Hydropathy evidently formed an important part of the treatment in the reconstructed temple. (See Fig. 2.) As has been shown above, the climate, the freedom from disturbing factors of all kinds, the existence at that spot of a plentiful supply of pure water, the character of the structures composing the temple group, and the widespread belief among the people that the Asclepiadae were able, with the assistance of the god Aesculapius, to effect cures which were obtainable nowhere else--all contributed to make the temple at Cos one of the greatest sanatoria of ancient times. [Illustration: FIG. 2. BIRD’S-EYE VIEW OF THE TEMPLE OF AESCULAPIUS AND ASSOCIATED BUILDINGS ON THE ISLAND OF COS. As they appeared in the third century B. C. (Copied by permission from a model made by Prof. Dr. Meyer-Steineg for the Medico-historical Museum of the University of Jena, Germany.)] [Illustration: FIG. 3. GROUND PLAN OF THE ASCLEPIEION ON THE ISLAND OF COS. As Ascertained by the Researches of Dr. Herzog. The different structures are arranged as nearly as possible in the same positions which they occupied in the third century, B. C.