Kassel (; spelled Cassel until 1928) is a town located on the Fulda River in northern Hesse, Germany. It is the administrative seat of the Regierungsbezirk Kassel and the Kreis of the same name and has approximately 195,000 inhabitants. The former capital of the state Hesse-Kassel has many palaces and parks, one of them the Bergpark Wilhelmshöhe which is a UNESCO World Heritage Site. Kassel is also known for the documenta exhibitions of contemporary art.
The city's name is derived from the ancient Castellum Cattorum, a castle of the Chatti, a German tribe that had lived in the area since Roman times.
Kassel was first mentioned in 913 AD as the place where two deeds were signed by King Conrad I. The place was called Chasella and was a fortification at a bridge crossing the Fulda river. A deed from 1189 certifies that Kassel had city rights, but the date when they were granted is not known.
In 1567, the landgraviate of Hesse, until then centered in Marburg, was divided among four sons, with Hesse-Kassel (or Hesse-Cassel) becoming one of its successor states. Kassel was its capital and became a centre of Calvinist Protestantism in Germany. Strong fortifications were built to protect the Protestant stronghold against Catholic enemies. In 1685, Kassel became a refuge for 1700 Huguenots who found shelter in the newly established borough of Oberneustadt. Landgrave Charles, who was responsible for this humanitarian act, also ordered the construction of the Oktagon and of the Orangerie. In the late 18th century, Hesse-Kassel became infamous for selling mercenaries (Hessians) to the British crown to help suppress the American Revolution and to finance the construction of palaces and the landgrave's opulent lifestyle.
In the early 19th century, the Brothers Grimm lived in Kassel and collected and wrote most of their fairy tales there. At that time, around 1803, the landgravate was elevated to a principality and its ruler to Prince-elector. Shortly after, it was annexed by Napoleon and in 1807 it became the capital of the short-lived Kingdom of Westphalia under Napoleon's brother Jérôme. The electorate was restored in 1813.
Having sided with Austria in the Austro-Prussian War for supremacy in Germany, the principality was annexed by Prussia in 1866. The Prussian administration united Nassau, Frankfurt and Hesse-Kassel into the new Prussian province of Hesse-Nassau. Kassel ceased to be a princely residence, but soon developed into a major industrial centre as well as a major railway junction.
In 1870, after the Battle of Sedan, Napoleon III was sent as a prisoner to the castle of Wilhelmshohe above the city. During World War I the German military headquarters were located in the castle of Wilhelmshohe. In the late 1930s Nazis destroyed Heinrich Hübsch's Kassel Synagogue.
During World War II, Kassel was the Headquarters for Germany's Wehrkreis IX, and a local subcamp of Dachau concentration camp provided forced labour for Henschel facilities. The most severe bombing of Kassel in World War II destroyed 90% of the downtown area, some 10,000 people were killed, and 150,000 were made homeless. Most of the casualties were civilians or wounded soldiers recuperating in local hospitals, whereas factories survived the attack generally undamaged. Karl Gerland replaced the regional Gauleiter, Karl Weinrich, soon after the raid.
The Allied ground advance into Germany reached Kassel at the beginning of April 1945. The US 80th Infantry Division captured Kassel in bitter house-to-house fighting during 2–4 April 1945, which included numerous German panzer-grenadier counterattacks, and resulted in further widespread devastation to bombed and unbombed structures alike.
Post-war, most of the ancient buildings were not restored, and large parts of the downtown area were completely rebuilt in the style of the 1950s. A few historic buildings, however, such as the Museum Fridericianum (see below), were restored. In 1949, the interim parliament ("Parlamentarischer Rat") eliminated Kassel in the first round as a city to become the provisional capital of the Federal Republic of Germany (Bonn won). In 1964, the town hosted the fourth Hessentag state festival (again in 2013). In 1972 the Chancellor of West Germany Willy Brandt and the Prime Minister of the German Democratic Republic Willy Stoph met in Wilhelmshöhe castle for negotiations between the two German states. In 1991 the central rail station moved from "Hauptbahnhof" (today only for regional trains) to "Kassel-Wilhelmshöhe".