Rudolf IV, also known as Rudolf IV of Austria, was a significant historical figure who ruled as Duke of Austria from 1358 until his death in 1365. He was a member of the House of Habsburg and is often remembered for his efforts to enhance the power and prestige of his duchy. Rudolf IV was instrumental in promoting the development of Vienna, which became an important cultural and political center during his reign. Rudolf IV is particularly noted for his ambitious building projects, including the construction of the St. Stephen's Cathedral in Vienna. He also sought to elevate the status of his territory by obtaining the title of "Archduke," which was a significant step in the evolution of the Habsburg dynasty. His reign laid the groundwork for future Habsburg rulers and their influence in European politics.