The Habsburg Monarchy or Habsburg Empire is an umbrella term coined by historians to denote the numerous lands and kingdoms of the House of Habsburg, especially for those of the Austrian line. However, in practice, the Habsburg Monarchy (of the Austrian branch) has often been called simply "Austria".
Although from 1438 to 1806 (with the exception of 1742 to 1745), a member of the House of Habsburg was also Holy Roman Emperor. The Holy Roman Empire itself, over which the emperor exercised only very limited authority, was not considered to be part of the Habsburg Monarchy.
The Habsburg monarchy was a union of crowns, with no single constitution or shared institutions other than the Habsburg court itself, with territories inside and outside the Holy Roman Empire that were united only in the person of the monarch. The Habsburg Monarchy was formally unified from 1804 to 1867 as the Austrian Empire and from 1867 to 1918 as the Austro-Hungarian Empire.