Frederick IV, also known as Frederick of the Empty Pockets (German: Friedrich mit der leeren Tasche), a member of the House of Habsburg, was Duke of Austria from 1402 until his death. As a scion of the Habsburg Leopoldian line, he ruled over Further Austria and the County of Tyrol from 1406 onwards.
Frederick was the youngest son of Duke Leopold III and his wife Viridis, a daughter of Bernabò Visconti, Lord of Milan. According to the 1379 Treaty of Neuberg, his father ruled over the Habsburg Inner Austrian territories of Styria, Carinthia, Carniola, as well as over Tyrol and the dynasty's original Further Austrian possessions in Swabia.
Upon the death of Duke Leopold IV in 1411, the surviving younger brothers Frederick and Ernest again divided the Leopoldian possessions. With Further Austria, Frederick became undisputed ruler over the Habsburg territories in the Alsace region and of the Burgau margraviate. In 1417 he also inherited the former Kyburg estates from the extinct comital Habsburg-Laufenburg branch. Several border conflicts with the Republic of Venice led to the loss of Rovereto in the Lagarina Valley. Under the terms of the Western Schism, Duke Frederick sided with Antipope John XXIII, whom he helped on his flight from the Council of Constance in March 1415. The Luxembourg king Sigismund had John arrested in Breisgau and placed Frederick under the Imperial ban. Thanks to the support of the local populace he managed to keep Tyrol, though he lost the western Aargau, the Freiamt and County of Baden estates, in the old homeland of the Habsburgs, to the Swiss.
Frederick died at his court in Innsbruck, despite his nickname a rich man. His son and heir Sigismund was called der Münzreiche ("Rich in Coin"). Frederick was buried in the Cistercian abbey of Stams, Tyrol.