This nice souvenir sheet was issued on July 15,2010 commemorating 600 Years of Grunwald Battle.
In 1230, the Teutonic Knights, a crusading military order, moved to Kulmerland and launched the Prussian Crusade against the pagan Prussian clans. With support from the Pope and Holy Roman Emperor, the Teutons conquered and converted the Prussians by 1280s and shifted their attention to the pagan Grand Duchy of Lithuania. For about a hundred years the Knights raided the Lithuanian lands, particularly Samogitia as it separated the Knights in Prussia from their branch in Livonia. The border regions became uninhabited wilderness, but the Knights gained very little territory. The Lithuanians first gave up Samogitia during the Lithuanian Civil War (1381–1384) in the Treaty of Dubysa. The territory was used as a bargaining chip to ensure Teutonic support for one of the sides in the internal power struggle.
In 1385, Grand Duke Jogaila of Lithuania proposed to marry reigning Queen Jadwiga of Poland in the Union of Kreva. Jogaila converted to Christianity and was crowned as the King of Poland thus creating a personal union between the Kingdom of Poland and Grand Duchy of Lithuania. The official Lithuanian conversion to Christianity removed the religious rationale for the Order's activities in the area. Its Grand Master, Conrad Zöllner von Rothenstein, supported by the Hungarian king Sigismund of Luxemburg, responded by publicly contesting the sincerity of Jogaila's conversion, bringing the charge to a papal court. The territorial disputes continued over Samogitia, which was in Teutonic hands since the Peace of Raciąż of 1404. Poland also had territorial claims against the Knights in Dobrzyń Land and Danzig (Gdańsk), but the two states were largely at peace since the Treaty of Kalisz (1343). The conflict was also motivated by trade considerations: the Knights controlled lower reaches of the three largest rivers (Neman, Vistula and Daugava) in Poland and Lithuania.
The Battle of Grunwald was fought on July 15, 1410, during the Polish–Lithuanian–Teutonic War. The alliance of the Kingdom of Poland and the Grand Duchy of Lithuania, led respectively by King Jogaila (Władysław Jagiełło) and Grand Duke Vytautas (Witold), decisively defeated the Teutonic Knights, led by Grand Master Ulrich von Jungingen. Most of the Teutonic knight's leadership was killed or taken prisoner. While defeated, the Teutonic Knights withstood the siege on their fortress in Marienburg (Malbork) and suffered only minimal territorial losses at the Peace of Thorn (1411) (Toruń). Territorial disputes continued until the Peace of Melno was concluded in 1422. However, the Knights never recovered their former power and the financial burden of war reparations caused internal conflicts and an economic downturn in their lands. The battle shifted the balance of power in Eastern Europe and marked the rise of the Polish–Lithuanian union as the dominant political and military force in the region.
The battle was one of the largest battles in Medieval Europe and is regarded as the most important victory in the history of Poland and Lithuania.It was surrounded by romantic legends and nationalistic propaganda, becoming a larger symbol of struggle against invaders and a source of national pride. During the 20th century, the battle was used in Nazi and Soviet propaganda campaigns. Only in recent decades have historians made progress towards a dispassionate, scholarly assessment of the battle reconciling the previous narratives, which differed widely by nation.