The decisive battle between Rudolph I of Habsburg and Ottokar II, Bohemian king of Přemyslid was fought on Marchfeld in 1278. This battle determined the fate of the two dynasties. Without the help of the Hungarian king, Ladislaus IV, the entire history of Central-Europe would have taken another direction. The German-Hungarian alliance won the battle, and this opened the way in front of the rise of the Habsburg dynasty.
The career of Ottokar II was extremely successful at the beginning. He was crowned to be Bohemian king in 1253, after conquering Lower Austria and Vienna. He took part in a crusade against the pagan Prussians and Lithuanians in alliance with the Teutonic Order between 1254-1255. Königsberg was named in honour of him.
As the prince of Austria, he wanted to get the entire heritage of the Babenberg dynasty (which died out in 1246), and after defeating the Hungarian army in 1260, led by Béla IV in the battle Kressenbrunn, he made a big step forward for that purpose – Styria was conquered. Continuing his conquest, he defeated the Hungarians again, led by István V and conquered the territories of Carinthia and Carniola in 1269 – later he also broke into Hungary and caused severe damage in Trans-Danube. As his dominion was growing and developing, he started to strive to become the Holy Roman Emperor and did everything he could for that purpose – extending his territories on the first place.
By 1272 he ruled from Silesia to the shores of the Adrian Sea within the Holy Roman Empire – so he had a serious chance of reaching his goal.
Being distrustful and afraid of his power, the prince-electors (Kurfürsten) elected the insignificant Swabian count Rudolph I. of Habsburg from Switzerland to be king of the Germans on 29th September 1273. Rudolph demanded the Austrian regions from Ottokar, which was automatically refused by the Bohemian king. In 1274 Ottokar was deprived of all his titles and rights of Ostmark, Styria, Carinthia and even Bohemia at the Diet of Regensburg. In 1276 he was excommunicated from the Empire, and Rudolph broke into his dominion. At the siege of Vienna, Ottokar was forced to surrender and sign a peace treaty – he had to resign from his Austrian dominions. He could only keep Bohemia and Moravia, and Rudolph occupied the rest of his territories.
After gathering his troops and reorganising his army, Ottokar was determined to get back all his lost territories. In 1278, he started a campaign against Vienna. Rudolph allied with Ladislaus IV. king of Hungary who had been offended by the Bohemian king before and saw Ottokar as the greatest danger of all.
On the battlefield of Marchfeld (between Dürnkrut and Jedenspeigen), the two vast armies collided on 26th August 1278.
It was one of the greatest cavalry battles of the Middle Ages.
The fights started with the Cuman cavalry’s (horse archers) hit and run tactics (shooting at the Bohemian cavalry and retreating quickly), disrupting the enemy lines. After that, the cavalry of Ottokar charged and attacked Rudolph’s line. In the meantime, the Hungarian cavalry destroyed the Bohemian right flank and ran down the enemy’s camp, slaughtering their crossbow units. Rudolph’s forces were about to break after his horse fell under him, and the German king’s life was barely saved. The Hungarian cavalry arrived back from the camp just in time and attacked from the rear of the Bohemian cavalry. After the Hungarian-German allied forces surrounded the Bohemian cavalry, the battle was decided. Ottokar saw that everything was lost, tried to break out with his remaining forces but failed. He tried to surrender but was cruelly slain by Rudolph’s cavalrymen who were driven by revenge.
The 16-year old Hungarian king, Ladislaus IV, stayed out of the fight and watched it from a safe distance. However, his forces turned the tides of the battle and saved Rudolph’s life and men, from inevitable defeat. Thanks to his contribution, the Habsburg dynasty could maintain its position in the Duchies of Austria and Styria. The rise of the Habsburg Empire could begin.