Hesse-Nassau was formed in 1867-1868 out of the territories which accrued to Prussia after the war of 1866, namely, the landgraviate of Hesse-Cassel and the duchy of Nassau, in addition to the greater part of the territory of Frankfort-on-Main, parts of the grand-duchy of Hesse, the territory of Homburg and the countship of HesseHomburg, together with certain small districts which belonged to Bavaria.
During the 18th century the War of the Austrian Succession and the Seven Years' War dealt heavy blows at the prosperity of the landgraviate, which was always loyal to the house of Austria.
The small landgraviate of Hesse-Homburg was formed in 1622 from Hesse-Darmstadt.
HesseHomburg was formed into a separate landgraviate in 1622 by Frederick I.
It was till 1866 a landgraviate and electorate of Germany, consisting of several detached masses of territory, to the N.E.