Frederick III was Duke of Austria and Styria for more than two decades in the 14th Century, sharing power with two of his brothers.

He was born in 1289. His father was the eventual Holy Roman Emperor Albert I, and his mother was Elizabeth of Carinthia. He was his parents' second-oldest son and had an older brother named Rudolf. When Albert was named King of Germany in 1298, he installed Rudolf, then 16, as his co-ruler for the Austrian lands. Technically, Rudolf and Frederick shared the titles of Duke of Austria and Duke of Styria. Also sharing those titles was a younger brother, Leopold.

In 1307, Rudolf took the field to put down a rebellion from the House of Strakonice. He died during the siege, on July 3. He left no heirs.

Frederick then ruled both Austria and Styria. His father was assassinated the following year, and replacing him as King of Germany was Count Henry VII of Luxembourg. Frederick came into conflict with his cousin Louis IV of Bavaria, and the conflict turned violent.

Louis defeated Frederick at the Battle of Gammelsdorf, on Nov. 9, 1313.

Just a few months earlier, the Holy Roman Emperor, Henry VII, had died, trying to secure authority over recalcitrant lands in Italy. The practice at the time was for a group of powerful nobles to elect their king, and these nobles had, at the time, been suspicious of endorsing the succession of kingship from father to son on the face of it, preferring to discuss and vote on such candidacies. Thus, Emperor Henry VII's son, John, was not an automatic successor. Henry VII was King of Germany as well; and while the nobles took their time coming to a decision about who their next ruler would be, the thrones of both Germany and the Holy Roman Empire were vacant.

Frederick was from the powerful House of Habsburg and had influential friends. At a gathering in Sachsenhausen on Oct. 19, 1314, a group of electors voted for Frederick as the next King of the Romans (or King of Germany); presiding over that gathering was Archbishop Henry II of Cologne. Louis was from the House of Wittelsbach, which also had powerful friends. A separate group of electors met in Frankfurt the day after Frederick was declared king, under the authority of Archbishop Peter of Mainz, and chose Louis as their next king. Further clouding the issue was the customary responsibility of the Archbishop of Cologne to crown the German king. Henry II did so, declaring Frederick's coronation in Bonn. However, Aachen was the ancestral home of German coronations since the time of Charlemagne, and so Archbishop Peter of Mainz duly crowned Louis in Aachen.

In 1315, Frederick married Isabella of Aragon. They had three children, two of whom lived into adulthood: Elizabeth (1317) and Anna (1318).

The political conflict descended into a military one, and Germany's most powerful nobles chose sides. The struggle went on for several years, with Frederick appearing ascendant more often than Louis did. However, Louis scored the knockout blow at Mühldorf, on Sept. 28, 1322, capturing Frederick and 1,300 nobles in the process. Louis held Frederick prisoner for three years but, bowing to political pressure from other leaders and from Pope John XXII, released his archrival. The two then agreed to the Treaty of Trausnitz, the terms of which saw Frederick recognizing Louis as the legitimate ruler. A further reconciliation saw the two rivals put aside their differences and agree to rule jointly, with Frederick taking the German crown and Louis taking the throne of the Holy Roman Empire. When Frederick's powerful brother Leopold died, in 1326, Frederick gave up the German crown and ruled only Austria.

Frederick returned to a relatively peaceful reign in Austria. He was at Gutenstein Castle when he died, on Jan. 13, 1330. He had no surviving son, and so his titles went to his younger brothers Albert II and Otto.