Leopold Day is an official holiday in Vienna, as well as in several other states of Austria. This day is celebrated annually on November 15 in memory of Saint Leopold of the Babenberg dynasty.

The ruler (margrave) of Austria, Leopold the Third, who lived at the turn of the 11th and 12th centuries, was a participant in a successful coup in the Holy Roman Empire (which included Austria), which earned him an increase in influence. The new emperor of the state, Henry, married his sister to Leopold and maintained close relations with him.

Leopold supported a peaceful foreign and domestic policy, contributed to the growth of the influence of the church, and was the founder of several famous monasteries (Klosterneuburg, Heiligenkreuz and Mariazell). As a result of such activities, in the 15th century he was canonized by the Catholic Church and recognized as the official patron saint of Vienna and Austria as a whole. Thus, he stands at the origins of the formation of independent Austria and the growth of its power.