The House of Habsburg had the largest territory in Medieval Europe. The House of Habsburg lasted for 700 years.
The Habsburg Empire is one of Prestigious Royal family in Medieval Europe.
The House of Habsburg made one in the family. Other than France, Europe has become one.
Cousin marriage is spread, Because... royal household became a jutting chin. It's a genetic problem.
The House of Habsburg became the Holy Roman Empire. And
The Habsburg Empire was of the Austro-Hungarian Empire.