Austria, under the rule of the Babenberg margraves since 976, has expanded eastward to the Hungarian border and southward into Styria and Carniola.

After their defeat at the 955 Battle of Lechfeld, the Magyars had discontinued their attacks on Germany and settled in the former Roman province of Pannonia, where they had established the Kingdom of Hungary.

The adjacent territories west of the Leitha were incorporated as the March of Styria into the Holy Roman Empire.

In 1180, Emperor Frederick Barbarossa had raised the Styrian lands to a duchy, which in 1192 had been acquired by the Austrian dukes from the House of Babenberg.

The Hungarian kingdom had suffered heavy losses since 1241 in the course of the Mongol invasion of Europe.

The Babenberg duke Frederick II, haughty and overambitious, makes use of this weakness, attacks Hungary, and claims the western comitati of Moson, …

…Sopron and …

…Vasvár.

King Bela IV makes a stand against the Austrian invasion: supported by the liensmen of his son-in-law, Prince Rostislav Mikhailovich, he gathers his troops and marches against Frederick's forces, which are challenged at the Battle of the Leitha River, in which the Babenberg ducal male line becomes extinct at the death of Frederick.

The battle sparks another conflict for the rule over the ceased Imperial fiefs of Austria and Styria.

Ottokar had been enticed by discontented nobles to lead the rebellion, during which he received the nickname "the younger King".

Wenceslaus managed to defeat the rebels and imprison his son.

Ottokar II had from July 31, 1248, to November 1249 held the title of King of Bohemia.

Herman VI, Margrave of Baden, had in 1248 married Gertrude of Austria, the niece of Duke Frederick II, and on the basis of this marriage claims the duchies of Austria and Styria, leaving the rule over Baden to his younger brother Rudolf.

Both the Emperor Frederick II and Margrave Herman VI are deceased by the end of 1250.

The latter having never been accepted by the Austrian nobles, Gertrude and their only son Frederick I, Margrave of Baden, continue their claim.

However, after the death of Emperor, no strong Imperial authority exists to assert his title.

Though he is backed by Pope Innocent IV and anti-king William of Holland, Frederick has been unable to prevail against the mighty Přemyslid king Wenceslaus I of Bohemia and his son Ottokar II, who upon Herman's death in 1250 occupies the Babenberg lands.