Hohenzollern-Sigmaringen was a principality in Southwestern Germany. Its rulers belonged to the senior Swabian branch of the House of Hohenzollern. The Swabian Hohenzollerns were elevated to princes in 1623. The small sovereign state with the capital city of Sigmaringen was annexed to the Kingdom of Prussia in 1850 following the abdication of its sovereign in the wake of the revolutions of 1848, then became part of the newly created Province of Hohenzollern. History The senior Swabian branch is not as well known to history, as is the junior Franconian line which became Burgraves of Nuremberg and later ruled Brandenburg and Prussia, and the German Empire. The County of Hohenzollern-Sigmaringen was created in 1576, upon the partition of the County of Hohenzollern, a fief of the Holy Roman Empire. When the last count of Hohenzollern, Karl I (1512–1579) died, the territory was divided among his three sons: Eitel Friedrich IV of Hohenzollern-Hechingen (1545–1605) Charles II of Hohenzollern-Sigmaringen (1547–1606) Christoph of Hohenzollern-Haigerloch (1552–1592) The Princes of Hohenzollern-Sigmaringen ruled over a small principality in southwest Germany, with a seat at Sigmaringen Castle. Unlike the Hohenzollerns of Brandenburg-Prussia, the Hohenzollerns of Sigmaringen remained Roman Catholic, along with their cousins of Hohenzollern-Hechingen (the senior line of the Swabian branch of the House of Hohenzollern) and Hohenzollern-Haigerloch. The principality became a sovereign state in 1815 after the abolition of the Holy Roman Empire in 1806 and an independent realm following the Napoleonic Wars in 1815. Its ruler, Charles, was deposed in the revolutions of 1848. His son, Karl Anton, succeeded him, and turned to Prussia for aid. Prussian troops arrived in August 1849, and in a treaty signed in December Hohenzollern-Sigmaringen was annexed by Prussia, effective in March 1850. The annexation of their state did not, however, mean the end of the importance of the House of Hohenzollern-Sigmaringen. The last prince, Karl Anton, served as Minister President of Prussia from 1858–61. Karl Anton's second son, Karl Eitel of Hohenzollern-Sigmaringen became prince (1866–1881) and then King of Romania, under the name Carol (reigned 1881–1914). The house remained on the throne until the end of the Romanian monarchy in 1947. The last King of Romania, Michael, died on 5 December 2017. Because the eldest Hechingen line of the Hohenzollerns became extinct in 1869 with the death of Constantine, Prince of Hohenzollern-Hechingen, the head of the Sigmaringen branch, Karl Anton, dropped his line's suffix and took the title of