Ottokar II, King of Bohemia, had at…
1276 CE
Ottokar II, King of Bohemia, had at the height of his power aimed at the Imperial crown, but the Princes-Electors (Kurfürsten), distrustful of his steep rise, had elected the "poor Swabian count" Rudolph of Habsburg King of the Romans on September 29, 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 had set the events of his demise in motion.
Placed under the Imperial ban in June 1276, he has had all his territorial rights revoked, including even his Bohemian inheritance.
Meanwhile, Rudolph is gathering allies and preparing for battle.
He achieves two of these alliances through the classic Habsburg style—marriage.
First, he marries his son Albert to Elisabeth of Gorizia-Tyrol.
In return, her father Count Meinhard II of Gorizia-Tyrol receives the Duchy of Carinthia as a fief.
Second, he establishes an—unstable—alliance with Duke Henry I of Lower Bavaria by offering him his daughter Katharina as wife for his son Otto in addition to the region of present-day Upper Austria as a pledge for her dowry.
He also concludes an alliance with King Ladislaus IV of Hungary, who intends to settle old scores with Ottokar.
So strengthened, Rudolph besieges Ottokar at the Austrian capital Vienna in 1276.
Many Austrian nobles chafe under Ottokar's rule; some have been executed for insurgence The Bavarian knights seize the amply provisioned center of Klosterneuberg near Vienna, and use the captured supplies to sustain Rudolph’s forces during the siege.
Ottokar had recently fortified the city, but his troops prove disloyal and desert.
He is 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 is determined to regain his territories and contracts an alliance with the Ascanian Margraves of Brandenburg and the Polish princes.