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. King Ottokar II of Bohemia expanded his territories considerably from 1250 to 1273, but suffered a devastating defeat in November 1276, when the newly elected German king Rudolph I of Habsburg imposed the Imperial ban on Ottokar, declaring him an outlaw and took over Ottokar's holdings in Austria, Carinthia, Carniola, and Styria. Ottokar was reduced to his possessions in Bohemia and Moravia, but was determined to regain his dominions, power, and influence. In 1278 he invaded Austria, where parts of the local population, especially in Vienna, resented Habsburg rule. Rudolf allied himself with King Ladislaus IV of Hungary and mustered forces for a decisive confrontation. Ottokar abandoned his siege of Laa an der Thaya and advanced to meet the allies near Dürnkrut, north of Vienna. Both armies were composed purely of cavalry and were divided into three divisions that attacked the enemy piecemeal. In the first phase of the battle, the Cuman horse archers in the Hungarian army outflanked and distracted the Bohemian left flank by launching arrows while the Hungarian light cavalry crashed into the Bohemians, driving them from the field. In the second phase, a great collision of knights and heavy cavalry took place in the center, with Rudolf's forces being driven back. Rudolf's third division, led by the king personally, attacked and halted Ottokar's charge. Rudolf was unhorsed in the melee and nearly killed. At a decisive moment, a German cavalry force of 200 riders, commanded by Ulrich von Kapellen, ambushed and attacked the Bohemian right flank from the rear. Assailed from two directions at once, Ottokar's army disintegrated into a rout, and Ottokar himself was killed in the confusion and slaughter. The Cumans pursued and killed the fleeing Bohemians with impunity. The battle marked the beginning of the ascendancy of the House