The Battle on the Marchfeld (i.e. Morava Field; Czech: Bitva na Moravském poli; Hungarian: Morvamezei csata) 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. Although both sides had in their units also infantry, the battle itself was primarily a great collision of heavy knights cavalry, though the Cuman horse archers in the Hungarian army played a vital role. The battle was finally won by an ambush attack of the united German-Hungarian forces.
The deposition of Emperor Frederick II of Hohenstaufen by Pope Innocent IV in 1245 created a grave crisis for the Holy Roman Empire, as in the following decades several nobles were elected as Rex Romanorum and Emperor-to-be, none of whom were able to gain actual governing power upon the Emperor's death in 1250. That same year, Ottokar II, son of king Wenceslaus I of Bohemia, moved into the princeless Duchies of Austria and Styria. The last Babenberg duke Frederick II of Austria had been killed at the 1246 Battle of the Leitha River, in a border conflict he had picked with King Béla IV of Hungary. Ottokar II gained the support of the local nobility and was proclaimed Austrian and Styrian duke by the estates one year later.
In 1253 Ottokar II became Bohemian king upon the death of his father; the concentration of power on the western Hungarian border was viewed with suspicion by King Béla IV, who campaigned against Austria and Styria but was finally defeated at the 1260 Battle of Kressenbrunn. In 1268 Ottokar signed a contract of inheritance with Ulrich III, the last Carinthian duke of the House of Sponheim, and thus acquired Carinthia including the March of Carniola and the Windic March one year later. At the height of his power he aimed at the Imperial crown, but the Princes-Electors (Kurfürsten), distrustful of his steep rise, elected the "poor Swabian count" Rudolph of Habsburg King of the Romans on 29 September 1273.
As the election had taken place in his absence, Ottokar did not acknowledge Rudolph as King. Rudolph himself had promised to regain the "alienated" territories which had to be conferred by the Imperial power with consent of the Prince-electors. He claimed the Austrian and Carinthian territories for the Empire and summoned Ottokar to the 1275 Reichstag at Würzburg. By not appearing before the Diet, Ottokar set the events of his demise in motion. He was placed under the Imperial ban and had all his territorial rights revoked, including even his Bohemian inheritance.
Meanwhile, Rudolph was gathering allies and preparing for battle. He achieved two of these alliances through the classic Habsburg style – marriage. First, he married his son Albert to Elisabeth of Gorizia-Tyrol. In return, her father Count Meinhard II of Gorizia-Tyrol received the Duchy of Carinthia as a fief. Second, he established an — unstable — alliance with Duke Henry I of Lower Bavaria by offering Rudolph's daughter Katharina as wife for the Duke's son, Otto, in addition to the region of present-day Upper Austria as a pledge for her dowry. He also concluded an alliance with King Ladislaus IV of Hungary, who intended to settle old scores with Ottokar.
Rudolph, so strengthened, besieged Ottokar at the Austrian capital Vienna in 1276. Ottokar was forced to surrender and to renounce all his acquisitions, receiving only Bohemia and Moravia as a fief from King Rudolph. Heavily deprived by this, he was determined to regain his territories and contracted an alliance with the Ascanian Margraves of Brandenburg and the Polish princes. In 1278 he campaigned against Austria, supported by Duke Henry I of Lower Bavaria, who had switched sides. Ottokar first laid siege to the towns of Drosendorf and Laa an der Thaya near the Austrian border, while Rudolph decided to leave Vienna and to face the Bohemian army in an open pitched battle in the Morava basin north of the capital, where the Cuman cavalry of King Ladislaus could easily join his forces.
Surprised by Rudolph's maneuver, Ottokar quickly abandoned the siege at Laa, marched southwards, and on August 26 met the united German and Hungarian forces near Dürnkrut. When he arrived his enemies had already taken the opportunity to explore the topography of the future battleground. From the early morning, the left wing of the advancing Bohemian troops were embroiled in impetuous attacks by the Cuman forces, which the heavy-armed knights could not ward off. Nevertheless, as the main armies collided and the battle wore on, Ottokar's outnumbering cavalry seemed to gain the upper hand, when even Rudolph's horse was stabbed under him and the 60-year-old narrowly escaped with his life, rescued by his liensmen.
After three hours of continued fighting on a hot summer day, Ottokar's knights in their heavy armour were exhausted, many of them suffered from circulatory failure and were not able to move. At noon Rudolph ordered a fresh heavy cavalry regiment he had concealed behind nearby hills and woods to attack the right flank of Ottokar's troops. Such ambushes were indeed commonly regarded as dishonourable in warfare and Rudolph's commander Ulrich von Kapellen apologized to his own men in advance. Nevertheless, the attack prevailed in splitting and stampeding the Bohemian troops. Ottokar realized the surprise attack and tried to lead a remaining reserve contingent in the rear of von Kapellen's troops, a maneuver that was misinterpreted as a rout by the Bohemian forces. The following collapse resulted in a complete victory of Rudolph and his allies. Ottokar's camp was plundered, and he himself was found slain on the battlefield.
Rudolph, to demonstrate his victory, had Ottokar's body displayed in Vienna. The "poor count" from Swabian Habsburg Castle assured his possession of the Duchies of Austria and Styria, the heartland and foundation of the rise of the House of Habsburg. At the 1282 Diet of Augsburg, he installed his sons Albert and Rudolf II as Austrian dukes; their descendants held the ducal dignity until 1918. However, in Bohemia, Rudolph acted cautiously and reached an agreement with the nobility and Ottokar's widow Kunigunda of Slavonia on the succession of her son Wenceslaus II to the throne. On the same occasion he reconciled with the Brandenburg margraves, ceding them the guardianship over the minor heir apparent. King Ladislaus IV exerted himself in the christianization of the Cuman warriors, before he was assassinated in 1290.
Ottokar's son, the young king Wenceslaus II of Bohemia, turned out to be a capable ruler. In 1291 he acquired the Polish Seniorate Province at Kraków and was crowned King of Poland in 1300. He was even able to secure the Hungarian crown for his son Wenceslaus III, still a minor, who nevertheless was murdered in 1306, one year after his father's death, whereby the Přemyslid dynasty became extinct.
The battle was depicted in art especially during the rise of nationalism in the 19th century, when it was viewed as the example of a traditional cooperation between Habsburg dynasty (Austria) and Kingdom of Hungary from one side and the traditional tension between Habsburg dynasty and Bohemia from the Czech side.
The tragedy König Ottokars Glück und Ende written by Franz Grillparzer in 1823 is based on the rise and fall of king Ottokar II. This drama was originally inspired by the life of Napoleon, though Grillparzer, fearing Metternich's censorship, chose to write the play about Ottokar, in whose story he found many parallels. It nevertheless was immediately forbidden and could not be performed until 1825. Grillparzer perpetuated the legend of Ottokar's wife Margaret of Babenberg unsuccessfully trying to reconcile the opponents on the eve of the battle. In fact, Margaret had died already in 1266.
The opera The Brandenburgers in Bohemia composed by Czech composer Bedřich Smetana in 1863 was inspired by this battle and following events as well.