The history of the city goes back to 775, when the first to-be suburbs "Wieseck" and "Unsenheim" were first mentioned. Gießen itself was founded by Graf Wilhelm von Gleiberg as a waterside-castle. In 1607, the University of Gießen was founded.
Heavy bombing destroyed about 75% of Gießen in 1944, including most of the city's historic buildings.
In 1977 Gießen was merged with the neighboring city Wetzlar to form the new city Lahn, however this attempt to reorganize the administration was very unpopular and was reverted in 1979.
The University of Giessen was founded in 1607 as a Lutheran university in the city of Giessen in Hesse-Darmstadt because the all-Hessian Landesuniversität, the nearby University of Marburg (Philipps-Universität Marburg) in Marburg, Hesse-Kassel, founded in 1527, had become Reformed (that is, Calvinist).
Belonging to a very small and poor German state, Giessen was always a minor and poor German university, a "stepping-stone university" where professors had their very first chair but moved on as soon as they could (with the exception of the strong agricultural and veterinary fields).
Next to Liebig, famous Giessen professors included the theologian Adolf von Harnack, the lawyer Rudolf von Jhering, the economist and statistician Etienne Laspeyres, the physicist Wilhelm Conrad Röntgen, the gestalt psychologist Kurt Koffka, the philologist and archaeologist Friedrich Gottlieb Welcker, and the orientalist Eberhard Schrader.
The Giessen Depot, once known as the Giessen Support Center, also home of the 284th BSB Headquarters, is located in Giessen, a city situated in northeast Hesse approximately 60 miles north of Hanau.
Giessen, the capital city of the former province of Upper Hessen, lies in the confluence of the Wieseck Brook and Lahn River.
Thus, Giessen is situated in the geographical center, north to south, of the German Federal Republic (West Germany), near the center of the State of Hessen.