Hesse (, , ) or Hessia (, ; ), officially the State of Hesse (), is a state in Germany. Its capital city is Wiesbaden, and the largest urban area is Frankfurt, which is also the country's principal financial centre. Two other major historic cities are Darmstadt and Kassel. With an area of 21,114.73 square kilometers and a population of over six million, it ranks seventh and fifth, respectively, among the sixteen German states. Frankfurt Rhine-Main, Germany's second-largest metropolitan area (after Rhine-Ruhr), is mainly located in Hesse. As a cultural region, Hesse also includes the area known as Rhenish Hesse (Rheinhessen) in the neighbouring state of Rhineland-Palatinate. Name The German name Hessen, like the names of other German regions (Schwaben "Swabia", Franken "Franconia", Bayern "Bavaria", Sachsen "Saxony"), derives from the dative plural form of the name of the inhabitants or eponymous tribe, the Hessians (Hessen, singular Hesse). The geographical name represents a short equivalent of the older compound name Hessenland ("land of the Hessians"). The Old High German form of the name is recorded as Hessun (dative plural of Hessi); in Middle Latin it appears as Hassonia, Hassia, Hessia. The name of the Hessians ultimately continues the tribal name of the Chatti. The ancient name Chatti by the 7th century is recorded as Chassi, and from the 8th century as Hassi or Hessi. An inhabitant of Hesse is called a "Hessian" (German: Hesse (masculine), plural Hessen, or Hessin (feminine), plural Hessinnen). The American English term "Hessian" for 18th-century British auxiliary troops originates with Landgrave Frederick II of Hesse-Kassel hiring out regular army units to the government of Great Britain to fight in the American Revolutionary War. The English form Hesse was in common use by the 18th century, first in the hyphenated names of the states of Hesse-Cassel and Hesse-Darmstadt, but the latinate form Hessia remained in common English usage well into the 19th century. The European Commission uses the German form Hessen, even in English-language contexts, due to the policy of leaving regional names untranslated. The synthetic element hassium, number 108 on the periodic table, was named after the state of Hesse in 1997, following a proposal of 1992. History The territory of Hesse was delineated only in 1945, as Greater Hesse, under American occupation. It corresponds only loosely to the medieval Landgraviate of Hesse. In the 19th century, prior to the unification of Germany, the territory of what