The first Habsburg who can be reliably traced was a certain Kanzelin, who died in the late 10th century; legend has the family name originating with the Habsburg Castle in modern Switzerland. After 1279, they came to rule in Austria. The Duchy of Austria was part of the elective Kingdom of Germany within the Holy Roman Empire. King Rudolf I of Germany of the Habsburg family assigned the Duchy of Austria to his sons at the Diet of Augsburg (1282), thus establishing the "Austrian hereditary lands". From that moment, the Habsburg dynasty was also known as the House of Austria. Between 1438 and 1806, with few exceptions, the Habsburg Archduke of Austria was elected Holy Roman Emperor.