This mountainous region has been a cockpit of struggle from very early times, but the difficult nature of the country has enabled the wild and turbulent highlanders to maintain their independence against Turk and Persian and Russian alike. Not until 1835 did Russia begin to annex the country; she did not come into full possession of it until more than forty years later. Before I describe the actual fighting let us look a little closer at this Russian government of the Caucasus.[178] Its main features are the great block of the Caucasus range and the lower mountain region to the south, known as Georgia. Between the two, at a distance of about sixty miles from the high ridge of the Caucasus, is a natural trench which rises gradually from the Black Sea for 3,000 feet to the watershed, and then slopes down to the Caspian Sea. Along this depression from Batum, on the Black Sea, to the great oil town of Baku, on the Caspian Sea, runs the railway which I have already mentioned. On it, about half-way between Batum and Baku, and also on the chief road which crosses the Caucasus, is Tiflis, the capital. It stands on the valley floor, surrounded by gray heights rising from twelve to fifteen hundred feet above it, and occupies both banks of the river Kur. The fighting which I am going to describe all took place to the south of Tiflis, between the depression mentioned above and the Turkish border. You will notice that a railway runs south from Tiflis amidst the Georgian mountains, and then swings eastwards to the frontier. This railway has to climb two ridges of fairly high mountains, and at its railhead of Sarikamish it is 6,000 feet above sea-level. The whole country through which it passes is a wild confusion of high hills with summits of 10,000 feet in elevation, and deep gorges, leading up to the Armenian plateau which I mentioned on page 270. It is impossible to get from one valley to another, except by the railway, without climbing steep and snow-clad ridges. You can scarcely conceive of a more difficult country in which to carry on the operations of war. [Illustration: The Campaign on the Caucasian Frontier. (Inset--The Turkish Advance.)] For the Caucasus campaign which the Turks were now about to begin they collected at Erzerum an army of 150,000 men with which to oppose the Russian army, which was not more than 100,000 strong. The object of the Turks was to capture the fortress of Kars, and thus open the way to Tiflis and to the Caspian oil fields at Baku. In order to do this they proposed to entice the Russians from Sarikamish across the frontier, and hold them at some point as far from the railhead as possible. While the Russian front was thus held, the Turks intended to make a wide encircling movement with their left centre and fall upon Sarikamish. At the same time, their left was to push up the Choruk River, cross the mountains to Ardahan, follow the road to Kars, and thus take the fortress in the rear.