Frederick III. of Austria was a member of the House of Habsburg and served as the duke of Austria and Styria from 1308 until his death. He is most known for his rivalry with Louis IV of Bavaria, which culminated in a struggle for the title of Holy Roman Emperor during the early 14th century.
Frederick was born in 1289 as the second son of Albert I of Habsburg, who later became the King of Germany and the Holy Roman Emperor. Frederick's mother, Elisabeth of Tirol, was the daughter of Count Meinhard II. of Gorizia-Tyrol.
In 1308, after the assassination of his father Albert I., Frederick and his brother Leopold I. jointly inherited the duchies of Austria and Styria. As co-rulers, they worked together to govern their territories and protect the interests of the Habsburg dynasty.
Following the death of Emperor Henry VII. in 1313, both Frederick and Louis were elected as King of the Romans by different factions of the electoral princes, leading to a contested claim to the title of Holy Roman Emperor. This conflict, known as the Double Election of 1314 sparked a series of political and military struggles between the Habsburg and Wittelsbach factions.
The rivalry between Frederick and Louis escalated into armed conflict in 1322 when the two armies clashed at the Battle of Mühldorf. Frederick was defeated and captured by Louis' forces, and he was subsequently imprisoned for several years. During his captivity, Frederick's brother Leopold continued to rule Austria and Styria and maintained the Habsburg opposition to Louis' claim to the imperial title.
In 1325, after lengthy negotiations, Frederick was released from captivity under the condition that he would recognize Louis as the legitimate Holy Roman Emperor. Although Frederick initially agreed to these terms, the conflict between the Habsburgs and the Wittelsbachs continued after his release, and it was not until the Treaty of Trausnitz in 1335 that a more lasting peace was achieved between the two dynasties.
Frederick died in 1330, and his brother Leopold continued to rule Austria and Styria until his own death in 1326.