[Sidenote:  Historical contrast between base and extremity.]

The Balkan Peninsula tells much the same story of contrasted geographic conditions and development in its continental and peninsular sections.  Greece proper, in ancient as in modern times, reached its northern confines where the peninsula suddenly widens its base through Macedonia and Thrace.  In this narrow southern section to-day, especially in isolated Peloponnesus, Attica, and the high-walled garden of Thessaly, are found people of the pure, long-headed, Hellenic type, and here the Greek language prevails.[787] But that broad and alien north, long excluded from the Amphictyonic Council and a stranger to Aegean culture in classical times, is occupied to-day by a congeries of Slavs, who form a southwestern spur of the Slav stock covering eastern Europe.  Its political history shows how often it has been made a Danubian or continental state, by Alexander of Macedon, by the Romans, Bulgarians, and Ottoman Turks,[788] as it may be some day by Russia; and also how often its large and compact form has enabled it to dominate the tapering peninsular section to the south.

In the same way, the vast Ganges and Indus basins, which constitute the continental portion of India, have received various Tibetan, Scythian, Aryan, Pathan, and Mongol-Tartar ingredients from Central Asia; and by reason of the dense populations supported by these fruitful river plains, it has been able to dominate politically, religiously and culturally the protruding triangle of the Deccan. [See maps pages 8 and 102.] The continental side of Arabia, the Mesopotamian valley which ties the peninsula to the highlands of Persia and Armenia, has received into its Semitic stock constant infiltrations of Turanian and Aryan peoples from the core of Asia.  This process has been going on from the ancient Elamite and Persian conquests of Mesopotamia down to the Ottoman invasion and the present periodic visits of Kurdish shepherds to the pastures of the upper Tigris.[789] Here we have the same contrast of geographic conditions as in Italy and India, a wide, populous alluvial plain occupying the continental section of the peninsula, and a less attractive highland or mountainous region in the outlying spur of land.

[Sidenote:  Continental base a scene of invasion and war.]

These continental sections of peninsulas become therefore strongly marked as areas of ethnic characterization and differentiated historical development.  Their threshold location, by reason of which they first catch any outward migration from the core of the continent, and their fertility, which serves as a perennial lure to new comers, whether peaceful or warlike, combine to give them intense historical activity.  They catch the come and go between their wide hinterland and the projection of land beyond, the stimulus of new arrivals and fresh blood.  But tragedy too is theirs.  The Po Valley has been called “the cockpit of Europe.”  Even the little Eider, which marks the base of Jutland, has been the scene of war between Danes and Germans since the tenth century.[790] The Indus Valley has again and again felt the shock of conflict with invading hordes from the central highlands, and witnessed the establishment of a succession of empires.  Peace at the gates of the Balkan Peninsula has never been of long duration, and the postern door of Korea has been stormed often enough.