SCHWARZBURG, HOUSE OF

   one of the oldest noble families of Germany; first comes into authentic history in the 12th century with Count Sizzo IV. (the first to take the title of Schwarzburg), and in the 16th century divides into the two existing branches, the Schwarzburg-Sondershausen and Schwarzburg-Rudolstadt - which give their names to two sovereign principalities of Central Germany wedged in between Prussia and the lesser Saxon States, the latter embracing part of the Thuringian Forest; both are prosperous agricultural and mining regions.