Olsztyn, Poland (1410 AD)
The Battle of Grunwald, also known as the First Battle of Tannenburg, was one of the largest and most famous medieval engagements to have taken place in Eastern Europe. It pitted armies of an alliance between Poland and Lithuania against an invading army from Germany under the leadership of the Teutonic Knights. It essentially ended the German eastward expansion in the Middle Ages, checked the military power of the Teutonic crusaders, and helped to cement the growing importance of the Slavic realms in the Baltic region.
In the aftermath of the failure of the Crusades in the Holy Land, the order of the Teutonic Knights returned to Europe in the 13th century, where they became re-established in northeastern Germany. Desirous to continue their efforts, and to establish their own realm, they began to slowly expand eastward and along the shores of the Baltic Sea. Around the same time, large Slavic nations were achieving independence from the Mongols, and were slowly expanding westward.
For over 150 years the German state expanded with the blessing of the Holy Roman Empire, but the nearby nations of Poland and Lithuania were also growing more powerful. Clashes beteen the states became increasingly violent in the late 1300s, especially after the marriage of the Queen of Poland to the Grand Duke of Lithuania in 1385. This alliance posed a direct threat to the Germans, and the dispute broke into open war in 1409.
The Teutons launched a pre-emptive strike against the Poles, winning a few easy victories early on. The Poles raised their own army, and further reinforced with an army from Lithuania, launched a counteroffensive. After a brief truce, during which time the King of Bohemia attempted to mediate a solution, the war resumed in 1410. During the summer, a massive joint Polish-Lithuanian force invaded Prussia.
The battle unfolded in three stages. At first, the smaller but militarily superior German force held off the first Lithuanian assault, forcing the Lithuanians to retreat. The main battle was then joined between the Germans and Poles. The fighting was roughly even, and both sides took heavy casualties. However, the Lithuanians then returned to the fight, striking the exhausted German army in the rear. The Teutonic Knights were forced to withdraw, and though they ultimately survived the war, never recovered their full strength again.
The Battle of Grunwald actually took place between what are now the towns of Grunwald and Stebark. Despite the Polish victory, the location of the battlefield remained under German control due to the subsequent peace treaty, and remained so until after World War I. Because of this, it was not until 1945 that the battlefield became a national historic site in Poland. The battle is now commemorated by a memorial monument and small museum where the fighting took place.
The Grunwald Battlefield is located just west of the city of Poznan, approximately 120 miles west of Warsaw. The memorial is an open site. As of this writing, no visitor information was available for the museum. Web: www.poznan.pl (official tourism website of Poznan).