Polish (Civ3)/Civilopedia

There can be little doubt that, had they been able to overcome their internal divisions, the Poles would have been a dominant power in the Middle Ages. The first institution that can be called a Polish kingdom or nation arose in around 980 A.D., when a tribal leader named Mieszko united three major tribes in eastern Europe and converted to Catholicism. The concept of a dynasty had not yet caught on in that part of Europe, though, so successions were often extremely violent and chaotic. After Miezsko's rule, the fortunes of the Polish nation-state depended entirely on the ruthlessness and strength of will of its leader. Some of Mieszko's successors were strong and able to impose their wills on the fractious principalities and tribes of Poland and Pomerania, and thereby defend effectively against foreign, usually German or Bohemian, invasion. Others were not.
In 1226 C.E., just over two hundred years after Boleslaw II successfully reunited the Polish kingdom, Poland was deeply divided once again. Baltic tribes menaced the north and the German state of Brandenburg sought greater land and influence in the west. The Polish king, Conrad of Mazovia, decided to import an army to fight off both of these threats in exchange for an indefinite homeland in Poland. The army was the Teutonic Knights. They accepted Conrad's offer and, after arriving in northern Poland, waged several bloody campaigns of conquest against the German and Baltic occupiers. To Conrad's surprise, though, the Knights then decided that they would rather have their own country rather than a dependent homeland inside someone else's kingdom. Conrad had saved the Polish kingdom from outside invasion, only to be invaded from within.
Future Polish kings then had to deal not just with Germans, Bohemians and Lithuanians, but the restless and aggressive Teutonic Knights. As if that were not enough, in 1241 a major Mongol invasion force arrived in Silesia (southeastern Poland). The Poles were able to defeat the Mongols, but at huge cost. Vast lands were laid waste and thousands of soldiers perished. In 1330 tensions between the Teutonic Knights and Poland erupted into open war, and after many political and military stalemates, the Polish king Casimir III was able to expand and recover from the Mongol attack and the endless conflicts with Poland's neighbors. But despite holding firm, Casimir had to settle for survival rather than prosperity.
The golden age of Poland came at the end of the Middle Ages, when alliance with Lithuania led to a combined assault on the Teutonic Knights that culminated in the fated battle of Grunwald in 1410. The Knights were able to fight off one contingent of the allied force, but were crushed by the other. The Knights were not totally defeated, but they would never again exert their will upon Poland as forcefully as they had in the preceding two centuries. Casimir IV, perhaps the greatest Polish king, was able to capitalize on this success to unite the Polish succession lines with those of Hungary and Bohemia, creating, albeit briefly, an eastern European super-state that dominated the region culturally and militarily for two generations.