Reuss, two former German principalities, merged into Thuringia in 1920. In their final years they comprised two blocks, separated by part of Saxe-Weimar-Eisenach. The southern and larger block, or Oberland, with Schleiz and Greiz as chief towns, was bounded east by the kingdom of Saxony, south by Bavaria, west by Saxe-Meiningen and part of Schwarzburg-Rudolstadt, and northwest by an exclave of Prussian Saxony. The other block, Unterland, around Gera, was bounded east and west by Saxe-Altenburg and north by Prussian Saxony.
The ruling house of Reuss was traceable to the 12th century. All its male descendants bore the name Henry (in honour of Emperor Henry VI), necessitating complex numeration. The Plauen line of this family was subdivided about 1300 between a senior branch (extinct 1572) and a junior. The latter took the name Reuss from its head, Henry the Russian (so designated after a trip to Russia and marriage to a Galician princess). It became Lutheran and split itself in 1564 into three lines, Elder Reuss, Middle Reuss (extinct 1616), and Younger Reuss. Elder Reuss had its capital, Greiz, and other possessions in Oberland; Younger Reuss possessed Unterland, with the capital at Gera, and half of Oberland.
The heads of the Elder and Younger Reuss both acquired the rank of count of the Holy Roman Empire in 1673; Elder that of prince in 1778; and branches of Younger Reuss that of prince in 1806. Both lines entered the German Confederation in 1815 and became members of the German Empire in 1871.
The two territories, which became free states in 1918, merged themselves into a People’s State of Reuss on April 4, 1919. This was absorbed into the new Thuringia on May 1, 1920.