The "Elder Line", the Grafen Reuss zu Greiz, Untergreiz, und Obergreiz, were elevated to princely status in 1778. Its members bore the title Prince Reuss, ältere Linie, or Prince Reuss zu Greiz. The members of this line were numbered sequentially, the last series beginning with Heinrich I (born 1693) and ending with Heinrich XXIV (1878-1927).
The "Younger Line", the Grafen Reuss zu Gera, zu Schleiz, zu Lobenstein, zu Köstriz und zu Ebersdorf, shared a numbering sequence which began and ended roughly as centuries began and ended. This line became princes in 1806, and its members bore the title Prince Reuss, jüngere Linie, though they are also referred to by their branch names (e.g. Prince Reuss zu Koestritz). The designation jüngere Linie was dropped in 1930; the altere Linie had become extinct as its last member Heinrich XXIV renounced his rights in 1918 and died in 1927 unmarried.
The two Principalities of Reuss "Elder Line" and "Younger Line" were members of the German Confederation, of the North German Confederation, and of the German Empire. In 1920 the states of Reuss were incorporated into the new state of Thuringia.
A consequence of this naming system is that the male children within a single nuclear family are not numbered sequentially: The sons of Heinrich LXVII Reuss zu Schleiz were, in order, Heinrich V, Heinrich VIII, Heinrich XI, Heinrich XIV, and Heinrich XVI.
Fürsten Reuss, Elder Line, 1778-1918
Fürsten Reuss, Younger Line, 1806-1918