For a thousand years, the geography of the borderlands dictated their fate.

The borderlands lie in a flat plain, crushed between the civilizations of Europe and those of Asia. East of Poland, West of Russia, their lack of mountains, seas, deserts and canyons has always made the borderlands easy to conquer. Five centuries ago, an army on horseback could march from a castle on the Baltic to a fort on the Black Sea without meeting a physical obstacle greater than a fast-running river or a wide forest. Even now, a spy running East from Warsaw to Kiev would find nothing natural to obstruct him. Distances are great, but messages to the King or the Khan or the Grand Duke or the Czar have always been easier to send here than in the more mountainous parts of Europe, because so little stands in the way of the messenger.

The borderlands' featurelessness attracted invaders, and the most celebrated — the most threatening — always came from the East. Long after the Mongol invasion of the thirteenth century, the name of the Golden Horde was still uttered in whispers, and the fame of the Turks, who attacked again and again from the sixteenth century to the eighteenth, has persisted as well. From the North came the most destructive invaders — the rapacious Swedes, who destroyed the region utterly in the great Deluge of 1655, and the Muscovites who began their incursions into the borderlands at about the same time. The least expected invaders came from the South, where Moldovan princes rose up to claim more territory in the sixteenth century, and Cossacks rebelled, setting fire to villages, in the seventeenth. Those who ruled the longest always came from the West. From the twelfth century onwards, Poles and Lithuanians administered vast regions of the borderlands, while the Teutonic Knights controlled the northern Baltic corner, reigning for so long that their descendants, the Germans, came to believe East Prussia would belong to them in perpetuity.