From the Middle Ages, the state comprised the Duchy of Savoy, the Principality of Piedmont, the Duchy of Aosta, and the County of Nice, all of which were formally part of the Holy Roman Empire; however, the Savoyards often acted against the Emperor, repeatedly siding with the French during the Franco-Habsburg Wars.

The Final Act of the Congress of Vienna of 1815 refers to them as the "States of His Majesty the King of Sardinia".

These territories formed a composite state under the House of Savoy until the Perfect Fusion in 1847.

[2] By 1861, this unified state had acquired most of the other states on the Italian peninsula and formed the Kingdom of Italy, while its territories north and west of the Alps (including Savoy proper) became part of France.

Scholarship has debated and used several different terms to reference the often disjointed possessions under control of the House of Savoy.