https://en.wikipedia.org/wiki/Habsburg_Monarchy
The first Habsburg who can be reliably traced was a certain Radbot of Klettgau, who was born in the late 10th century; the family name originated with Habsburg Castle, in present-day Switzerland, which was built by Radbot. After 1279, the Habsburgs came to rule in the Duchy of Austria, which was part of the elective Kingdom of Germany within the Holy Roman Empire.