The head of the Austrian branch of the House of Habsburg was often elected Holy Roman Emperor: from 1415 until the Empire's dissolution in 1806, Charles VII of Bavaria (1742–1745) was the only Holy Roman Emperor who was not Habsburg ruler of Austria. The two entities were never coterminous, as the Habsburg Monarchy covered many lands beyond the Holy Roman Empire, and most of the Empire was ruled by other dynasties.
This Austrian Habsburg Monarchy must not be confused with the House of Habsburg, existing since the 11th century, whose vast domains were split up in 1521 between this "junior" Austrian branch and the "senior" Spanish branch.
The monarchy had no official name. Instead, various names included:
The Habsburg family originated with the Habsburg Castle in modern Switzerland, and after 1279 came to rule in Austria ("the Habsburg Hereditary Lands"). The Habsburg family grew to European prominence with the marriage and adoption treaty by Emperor Maximilian I at the First Congress of Vienna in 1515, and the subsequent death of adopted Louis II of Hungary and Bohemia in 1526.
Names of the territory that (with some exceptions) finally became Austria-Hungary:
The Hungarian parts of the Empire were called "Lands of the Holy Hungarian Crown of Saint Stephen" or "Lands of Holy (St.) Stephen's Crown" (Länder der Heiligen Stephans Krone). The Bohemian (Czech) Lands were called "Lands of the St. Wenceslaus' Crown" (Länder der Wenzels-Krone).