September 17th in History-1156

Austria becomes a duchy

Henry II Jasomirgott, (born c. 1114—died Jan. 13, 1177, Vienna), the first duke of Austria, a member of the House of Babenberg who increased the dynasty’s power in Austria by obtaining the Privilegium Minus (a grant of special privileges and a reduction of obligations toward the empire) from the Holy Roman emperor Frederick I Barbarossa when Austria was raised to a duchy.

https://www.britannica.com/biography/Henry-II-Jasomirgott#ref111302