The choice of these marshy or insulated sites is all the more singular from the environment. Around Lake Copaïs, about Tiryns and Amyclæ, as well as in Thessaly, rise mountains which are nature’s own fastnesses and which would seem to invite primitive man to their shelter. The preference for these lowland or island settlements then, can only be explained in the first instance by immemorial custom, and, secondly, by consequent inexperience in military architecture. Naturally, a lake-dwelling people will be backward in learning to build stone walls strong enough to keep off a hostile force. And in default of such skill, instead of settling on the mountain slopes, they would in their migrations choose sites affording the best natural fortifications akin to their ancient environment of marsh or lake--reinforcing this on occasion by a moat, an embankment, or a pile-platform. That the people in question once actually followed this way of living is beyond a doubt. Amyclæ shows no trace of wall, and probably never had any beyond a mere earthwork. The Cyclopean wall of Tiryns, as it now stands, does not belong to the earliest settlement, nor is it of uniform date. Adler holds that the first fortress must have been built of wood and sun-dried bricks. This construction may possibly account for those remarkable galleries whose origin and function are not yet altogether clear. The mere utility of the chambers for storage--a purpose they did unquestionably serve--hardly answers to the enormous outlay involved in contriving them. May we not, then, recognise in them a reminiscence of the primitive palisade-earthwork? In the so-called Lower Citadel of Tiryns we find no such passages, possibly because its Cyclopean wall was built at a later date. Likewise no proper galleries have yet been found at Mycenæ, and it is highly improbable that any such ever existed there. What had long been taken for a gallery in the north wall proves to be nothing but a little chamber measuring less than seven by twelve feet. Obviously, then, the gallery was not an established thing in fortress-architecture, and this fact shows that it did not originate with the builders of stone walls, but came to them as a heritage from earlier times and a more primitive art.