The House Order of Hohenzollern was instituted on December 5, 1841 by joint decree of Prince Konstantin ofHohenzollern-Hechingen and Prince Karl Anton of Hohenzollern-Sigmaringen. These two principalities in southern Germany were Catholic collateral lines of the House of Hohenzollern, cousins to the Protestant ruling house ofPrussia.
On August 23, 1851, after the two principalities had been annexed by Prussia, the order was adopted by the Prussian branch of the house. Also, although the two principalities had become an administrative region of the Prussian kingdom, the princely lines continued to award the order as a house order. The Prussian version was then known as the Royal House Order of Hohenzollern (Königlicher Hausorden von Hohenzollern or Königlich Hohenzollernscher Hausorden), to distinguish it from the Princely House Order of Hohenzollern (Fürstlicher Hausorden von Hohenzollern or Fürstlich Hohenzollernscher Hausorden). Although Kaiser Wilhelm II abdicated in 1918 as German Emperor and King of Prussia, he did not relinquish his role as Head of the Royal House and as such he was still able to confer the Royal House Order. The Princely House Order continued to be awarded, unofficially, after the fall of the German Monarchy.
Another development occurred in 1935. Prince Karl Anton's second son, Karl Eitel Friedrich of Hohenzollern-Sigmaringen, had become prince and then king of Romania as Carol I. Carol I had died childless and was succeeded by his nephew Ferdinand I, also of Hohenzollern-Sigmaringen. During the reign of Ferdinand's son King Carol II, the Romanian government established its own version of the House Order of Hohenzollern, known in Romanian as Ordinul "Bene Merenti" al Casei Domnitoare ("Order of 'Bene Merenti' of the Ruling House"). This form of the order existed until the Romanian monarchy was abolished in 1947; King Michael also awarded a slightly altered order in exile.