The curving chain of mountains below the Iron Gate is the Balkan Range. But excepting for the plains of Thrace, lying south of the Balkans, over toward the Black Sea and above Constantinople, the rest of the peninsula is almost entirely one confused tangle of craggy mountains, interspersed throughout with small, fertile valleys and plateaus. This roughness of surface becomes especially aggravated as one passes westward, and over toward the Adriatic coast, from Greece up into the Austrian province of Dalmatia, the country is almost inaccessible to ordinary travelers.
What is the political value of this beleaguered domain? The broad, significant fact is that any road from western Europe to the Orient must pass through the Balkan Peninsula, and that these mountains almost block that road. From north to south there is just one highway, so narrow that it is really a defile.
This road stretches from the seat of the war at Belgrade on the Danube down a narrow valley, the Morava, thence through the highlands of Macedonia into the Vardar Valley to Saloniki, on the Ægean Sea. At Nish, above Macedonia, another road branches off into Bulgaria across the plains of Thrace and into Constantinople. This was the road by which the Crusaders swarmed down to conquer the Holy Land. This was the road by which, hundreds of years later, the Moslems swarmed up into the plains of Hungary and overran the south of Europe, until they were finally checked outside the gates of Vienna. Nothing is more significant of the terror that these marching hosts inspired than the fact that, with the exception of a few larger towns, the villages hid themselves away from this highway in the hills.
Bear clearly in mind that in the existence of this narrow way to the Orient lies the key not only to the causes of the war, but to the military campaigns that we shall follow in this region. For it is the Teutons who would in the Great War, like the Crusaders of old, pass down this highway and again conquer the East, though in this case their object is trade, and not the Holy Sepulcher.
To secure the pathway through this strategic country it also is necessary to have control of the territory on all sides, and this is quite as true in a political as in a military sense. To secure their pathway up into Europe the Turks once conquered all the peoples in the Balkans, except those inhabiting the mountains over on the Adriatic: the Montenegrins and a small city called Ragusa, just above Montenegro in Dalmatia. It is not at all peculiar that just here, in almost the same locality, the Teutons should meet with the first and strongest resistance.