Mongol incursions in the Holy Roman Empire took place in the spring of 1241 and again in the winter of 1241–42. They were part of the first Mongol invasion of Europe.
The Mongols did not advance far into the Holy Roman Empire and there was no major clash of arms on its territory. Rather, the army that had invaded Poland, after harassing eastern Germany, crossed the March of Moravia in April–May 1241 to rejoin the army that had invaded Hungary. During their transit, they laid waste the Moravian countryside but avoided strongholds. King Wenceslaus I of Bohemia was joined by some German princes, but he monitored the Mongols in Moravia without seeking battle. There were more significant skirmishes in the north of the Duchy of Austria a month later that left several hundred dead, but there was no cooperation between the Austrians and Hungarians.
In response to the Mongol threat, the imperial church and the imperial princes held assemblies to organize a military response. Pope Gregory IX ordered the preaching of a crusade and from Italy Emperor Frederick II issued an encyclical to that end. A crusading army under the command of King Conrad IV of Germany mustered on 1 July 1241, but was disbanded a few weeks after setting out because the danger had passed.
Although there was no major military action in the Empire, rumours that the Mongols had been checked there spread far beyond the Empire's borders. There are records in several languages from Spain to Armenia of the Bohemian or German king defeating the Mongols and forcing their retreat. In Moravia, a supposed victory over the Mongols took on legendary proportions. In Germany, some contemporary writers attributed the Mongols' general retreat from Europe to the intimidating crusading army. In reality, the Mongols likely spared most of Germany because their primary objective was to punish the Hungarian king for supporting the Cumans.
The Mongols raided eastern Austria and southern Moravia again in December 1241 and January 1242. A century later in 1340 they raided the March of Brandenburg. Anti-Mongol crusades were preached within the Empire's borders several times between these two raids, and even as late as 1351.
Background
The general view in western Europe, since at least 1236, was that the Mongols' ultimate goal was the Holy Roman Empire. This was based partially on intelligence, but mainly on prevailing interpretations of apocalyptic literature. The arrival of the Mongols on the eastern border of the Empire presented the first serious external threat it had faced since the Hungarian invasions in the 10th century. The Empire was not well positioned to meet it. The emperor had been excommunicated since 1239 and the pope was arranging a political crusade against him in Italy.
In 1237, King Béla IV of Hungary received a Mongol ultimatum demanding his submission. According to Aubry of Trois-Fontaines, a similar ultimatum was received at the court of Emperor Frederick II in 1238, although this is not recorded by anyone else and no such document has survived. Frederick supposedly responded that he would gladly resign his crown if he could become the khan's falconer. The Annales Sancrucenses record that the Mongols also sent ambassadors to Duke Frederick II of Austria demanding his submission.
In his Chronica majora, Matthew of Paris records that rumours about the Mongols had spread into the empire by 1238, for which reason the fishmongers of Frisia were unwilling to go to England. He is also the source for the rumour that the Mongols were the Lost Tribes of Israel and were assisted by Jews smuggling arms out of Germany in wine barrels. The Jewish merchants were said to claim that the barrels were filled with poisoned wine for the invaders. Owing to these rumours, Jews were killed at several customs posts.
The Mongols entered Hungary on 12 March 1241. Béla IV immediately sent a letter requesting assistance to Duke Frederick. The duke arrived in Pest in the last weeks of March or the first week of April with a small contingent of poorly armed men. Frederick quickly won a small victory, killing two spies attached to the contingent under Shiban. Soon after the Cuman leader Köten was killed. Although the role of Frederick in this is uncertain, he left Pest not long after on bad terms with the Hungarian king.