Middle Ages

The origins of the castle lie in the Katzenelnbogen time.^[7] In the middle of the 13th century the counts of Katzenelnbogen built a moated castle in Darmstadt.^[7] In 1330 Darmstadt received town rights,^[8][9] one year later the castle is mentioned for the first time in a document.^[10] From 1386, the moated castle lost importance and became a widow's residence and secondary residence.^[11] In the following two centuries, the counts of Katzenelnbogen extended and rebuilt the castle again and again. Until the middle of the 15th century the castle was transformed into a representative castle and Darmstadt became Katzenelnbogen's second residence.^[12] What remains of the moated castle are the form of the central church courtyard and the outer walls of the manor house. When the last count von Katzenelnbogen died in 1479, Darmstadt fell to Henry III, Landgrave of Upper Hesse.^[7] When Philip I took over the government offices in 1518, the castle was destroyed for the first time in an attack by Franz von Sickingen.^[10] The castle was rebuilt in the following years, but with essentially the same defensive structures. During the Schmalkaldic War in 1546 it was destroyed again by imperial troops.^[7]

Renaissance era

Landgrave George I considerably extended the castle from 1567 to a Renaissance complex and secured it with moats and bastions. The half-timbered floors of the former palace and the hall are rebuilt from stone. The buildings received new roofs. Christoph Müller and Jakob Wustmann^[14] developed the old moated castle into a residential palace.^[7] After 1589 the office, the stables and the arsenal were built, which no longer exist today.^[15] From 1594, the landgrave had orphans educated in the castle. From 1595 to 1597 the Kaisersaal (Emperor's room) and the church were built. The tympanum corridor (Paukergang), which connects the manor with the church, was also built.^{[11][7][16][15]}

The Wallhäuschen, a gate building in the north of the castle, was built in 1627 by Jakob Müller. The bell building was built from 1663 to 1671 according to plans by the architect Johann Wilhelm Pfannmüller. The bells were delivered by Piter Hemony.^[17] Darmstadt was attacked by the French in 1693 and the castle burned down.^[18]

Baroque era

Landgrave Ernst Ludwig commissioned the French architect Louis Remy de la Fosse to plan a new baroque palace with four large wings in 1715, after the palace's chancellery had burned down.^[7] This was to completely replace the old palace. Due to lack of money, however, only two wings were completed by 1726. These were to remain the last major structural changes to the castle. When Hessen-Darmstadt joined the Confederation of the Rhine in 1806, the castle became the seat of the Grand Dukes of Darmstadt.^[19] At the beginning of the 19th century, the upper floors of the new castle were furnished and fitted with window glazing.^[11] In 1842, the university and state library and the grand ducal collection with natural history cabinet moved in.^[11] Since the 18th century the castle has been less and less inhabited by the grand dukes and other members of the ruling family who settled in more comfortable premises, most of which were destroyed in World War II. These included the Altes Palais [de] and Alexanderpalais [de] on Luisenplatz [de], the Neues Palais [de] and Prinz-Carl-Palais [de] to the south, the Prinz-Georg-Palais [de] to the north, and the Palais Rosenhöhe [de] near the family's burial grounds in Rosenhöhe Park [de] to the east. Meanwhile, more and more institutions were admitted in the vacant old residential palace and some of the rooms were reserved for state guests.^{[11][7][16][15]}

20th century

In 1893, under Ernst Ludwig, Grand Duke of Hesse and by Rhine, structural measures were again being taken. Thus the extension with a tea pavilion was built on the Herrenbau. In 1924, the castle museum moved into the old area of the castle.^[11][7][15]

After the World War I, the castle passed into the possession of the People's State of Hesse. On the night of the fire in Darmstadt from 11 to 12 September 1944, the castle burned down to the outer walls.^[20][21] Reconstruction began in 1946 and was not completed until the early 1970s.^[10] An overall repair was carried out in 2008, which is planned to last for a longer period of time.^[22] The bell construction was completed in 2016.^[23] The outer appearance was almost completely restored.^[23] As of 2023^[update], the castle is the seat of the Technische Universität Darmstadt and the German-Polish Institute [de].^{[11][16][15][24]}

Buildings

• Wallhaus (wall building)^[32]
• Brückenhaus (bridge building)^[32]
• Herrenbau, German-Polish Institute (manor)^[33]
• Weißer Saalbau, Schlosskeller, Department of History and Social Sciences (white hall)^[23][34]
• Kaisersaalbau (emperor's hall)^[32]
• Kirchenbau, Orgelsaal, Schlossmuseum (church building, organ hall, palace museum)^{[33][35][36][37]}
• Glockenbau with Glockenspiel, Schlossmuseum (bell building with carillon, palace museum)^[32]
• Prinz-Christian-Bau (Prince Christian building)^[23]
• De-la-Fosse-Bau,^[38] Library Department of History and Social Sciences, Executive Board of TU Darmstadt (Baroque castle)^[32]

Courtyards

• Kirchenhof (church yard)^[33]
• Glockenhof (bell yard)^[33]
• Parforcehof^[39]

Corridors

• Paukergang^[11]

Bridges

• Wallbrücke (wall bridge, north entrance)^[33]
• Marktbrücke (south main entrance)
• Parforce-Brücke (west entrance)

Outer fortifications

• Schlossgraben [de] (castle moat)^[40][41]

Source:^[3]