The Habsburg Monarchy (German: Habsburgermonarchie) or Empire is an unofficial appellation among historians for the countries and provinces that were ruled by the junior Austrian branch of the House of Habsburg between 1521 and 1780 and then by the successor branch of Habsburg-Lorraine until 1918. The Monarchy was a composite state composed of territories within and outside the Holy Roman Empire, united only in the person of the monarch. The dynastic capital was Vienna, except from 1583 to 1611, when it was moved to Prague.
From 1804 to 1867 the Habsburg Monarchy was formally unified as the Austrian Empire, and from 1867 to 1918 as the Austro-Hungarian Empire.
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.