Question: On what date did the battle named after the birthplace of Ingo Kober end?

full_context: Document 1: Battle of Liegnitz (1760): The armies collided around the town of Liegnitz (now Legnica, Poland) in Lower Silesia. Laudon's Austrian cavalry attacked the Prussian position in the early morning but were beaten back by General Zieten's Hussars. An artillery duel emerged which was eventually won for the Prussians when a grenade hit an Austrian powder wagon. The Austrian infantry then proceeded to attack the Prussian line, but was met with concentrated artillery fire. A Prussian infantry counter-attack led by the Regiment Anhalt-Bernburg on the left forced the Austrians into retreat. Notably, the Anhalt-Bernburgers charged Austrian cavalry with bayonets, a rare example of infantry assaulting cavalry.
Document 2: Battle on the Marchfeld: The Battle on the Marchfeld ("i.e. Morava Field"; ; ) at Dürnkrut and Jedenspeigen took place on 26 August 1278 and was a decisive event for the history of Central Europe for the following centuries. The opponents were a Bohemian (Czech) army led by the Přemyslid king Ottokar II of Bohemia and the German army under the German king Rudolph I of Habsburg in alliance with King Ladislaus IV of Hungary. With 15,300 mounted troops, it was one of the largest cavalry battles in Central Europe during the Middle Ages. The Hungarian cavalry played a significant role in the outcome of the battle.
Document 3: Lars Kober: Lars Kober (born 19 October 1976 in Berlin) is a German sprint canoer who competed in the late 1990s and early 2000s. He won a bronze medal in the C-2 1000 m event at the 2000 Summer Olympics in Sydney with Stefan Uteß.
Document 4: Ingo Petzke: Ingo Petzke (born 18 September 1947 in Belm near Osnabrück in Germany) is an internationally acknowledged German film scholar, filmmaker and author.
Document 5: Battle of Zhongdu: The Battle of Zhongdu (present-day Beijing) was a battle in 1215 between the Mongols and the Jurchen Jin dynasty, which controlled northern China. The Mongols won and continued their conquest of China.
Document 6: Ingo Kober: Ingo Kober (born 22 July 1942 in Liegnitz, now Legnica in Poland) was the third president of the European Patent Office.
Document 7: Battle of Legnica: The Battle of Legnica (), also known as the Battle of Liegnitz () or Battle of Wahlstatt (), was a battle between the Mongol Empire and the combined defending forces of European fighters that took place at Legnickie Pole ("Wahlstatt") near the city of Legnica in the Duchy of Silesia on 9 April 1241.
Document 8: King Jagiello Monument: The King Jagiełło Monument is an equestrian monument of Władysław II Jagiełło, King of Poland and Grand Duke of Lithuania, located in Central Park, New York City. The monument commemorates the Battle of Grunwald, a decisive defeat of the Teutonic Order in 1410. Originally made for the Polish 1939 New York World's Fair pavilion, the monument was permanently installed in Central Park in 1945. Raised on its grand plinth it is one of the most prominently-sited and impressive of twenty-nine sculptures located in the park.
Document 9: Battle of Mohi: The Battle of Mohi (today Muhi), also known as Battle of the Sajó River or Battle of the Tisza River (11 April 1241), was the main battle between the Mongol Empire and the Kingdom of Hungary during the Mongol invasion of Europe. It took place at Muhi, southwest of the Sajó River. After the invasion, Hungary lay in ruins. Nearly half of the inhabited places had been destroyed by the invading armies. Around 15–25 percent of the population was lost, mostly in lowland areas, especially in the Great Hungarian Plain, the southern reaches of the Hungarian plain in the area now called the Banat and in southern Transylvania.
Document 10: Battle of Grunwald: The Battle of Grunwald, First Battle of Tannenberg or Battle of Žalgiris was fought on 15 July 1410 during the Polish–Lithuanian–Teutonic War. The alliance of the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania, led respectively by King Władysław II Jagiełło (Jogaila) and Grand Duke Vytautas, decisively defeated the German–Prussian Teutonic Knights, led by Grand Master Ulrich von Jungingen. Most of the Teutonic Knights' leadership were killed or taken prisoner. Although defeated, the Teutonic Knights withstood the siege of their fortress in Marienburg (Malbork) and suffered minimal territorial losses at the Peace of Thorn (1411) (Toruń), with other territorial disputes continuing until the Peace of Melno in 1422. The knights, however, would never recover their former power, and the financial burden of war reparations caused internal conflicts and an economic downturn in the lands under their control. The battle shifted the balance of power in Central and Eastern Europe and marked the rise of the Polish–Lithuanian union as the dominant political and military force in the region.
Document 11: Görres Society: The Görres Society was founded on 25 January 1876 in Koblenz by Catholic scientists and writers as the "Görres-Gesellschaft zur Pflege der katholischen Wissenschaften" in honour of Joseph Görres to advance Roman Catholic studies. Co-founder, initiator and first president was Georg von Hertling, the later "Reichskanzler" of Germany.
Document 12: Eckehard Specht: Eckehard Specht is a professor in Otto von Guericke University, Magdeburg, Germany. He belongs to Institute of Fluid Dynamics and Thermodynamics (ISUT) department. His specializations are Combustion technology, heat and mass transfer, chemical process engineering, global warming, and ceramic materials.
Document 13: Mongol invasion of Kievan Rus': In mid-1238, Batu Khan devastated the Crimea and pacified Mordovia. In the winter of 1239, he sacked Chernigov and Pereyaslav. After many days of siege, the horde stormed Kiev in December 1240. Despite the resistance of Danylo of Halych, Batu Khan managed to take two of his principal cities, Halych and Volodymyr - Volynskyi. The Mongols then resolved to ``reach the ultimate sea '', where they could proceed no further, and invaded Hungary and Poland.
Document 14: Horst H. Berger: Berger was born in Liegnitz (Legnica), Lower Silesia, and received the Vordiplom. from the Technische Hochschule of Dresden, then worked at the IBM Laboratories in Böblingen. Afterwards he became a researcher and teacher at the Technical University of Berlin.
Document 15: Johann Kasimir Kolbe von Wartenberg: Johann Kasimir Kolbe von Wartenberg (6 February 1643, in Wetterau – 4 July 1712, in Frankfurt am Main) was the first ever Minister-President (effectively Prime Minister) of the kingdom of Prussia, and the head of the "Cabinet of Three Counts".
ground_truth: 9 April 1241
sub_queries: Ingo Kober >> place of birth Answer: Legnica
On what date did Battle of Legnica end? Answer: 9 April 1241