[1][2] The castle was the headquarters of the ducal lines of the house of Glücksburg and temporarily served as the primary residence of the Danish monarch.
The history of today's castle grounds began in Schleswig in 1192, when the double monastery of St. Michael auf dem Berge was dissolved.
The nuns then moved to the St. John's Monastery [de] in Schleswig, which still exists today, while the monks left the place and went to Guldholm on Langsee.
The Danish King Frederick II encumbered his brother John, known as Hans the Younger, with the lands of Sundewitt, the Reinfeld monastery and the old Ryd Abbey, amongst other things.
As a typical duke of his time, he expressed his wealth with various buildings and founded, among other things, the castles in Reinfeld and Ahrensbök, which have since been demolished.
John's son Philipp received the castle and the lands of Glücksburg and thus founded the first, the elder line of the House of Schleswig-Holstein-Sonderburg-Glücksburg.
in 1825, The Danish King Frederick VI handed over the fief and thus the castle and title to his brother-in-law Friedrich Wilhelm from the Holstein-Beck family.
Together with his wife, Louise Caroline, a daughter of the ducal governor Charles von Hessen-Kassel, he founded the younger line of the House of Glücksburg.
With the war, the long personal union of the Danish royal family and the Schleswig-Holstein duchies ended, and the castle passed into Prussian ownership.
The Flensburger Nachrichten newspaper reported on September 22: "[...] Glücksburg had festively adorned itself for the arrival of the king; There were three gates of honor, one at Ruhethal, the second in front of the entrance to the town, the third at the driveway to the castle, and flags and floral decorations in abundance.
The king arrived the 16th, at 3 p.m., at the second gate of honor, Pastor Vogel gave a brief address, which the monarch graciously returned.
A few peasant girls had gathered at the castle to offer the father of the country butter, bread, cheese and fruit as well as fishing products.
The following resided here as descendants of Duke Karl († 1863): One of the most famous regular guests was Auguste Viktoria, the last German Empress, who came from the closely related house of Schleswig-Holstein-Sonderburg-Augustenburg .
Towards the end of World War II, under the Doenitz administration, Germany moved the seat of government to Mürwik in the city of Flensburg.
The return of the looted items followed an appeal to Queen Mary, mother of the British King George VI, who was a niece of Friedrich Ferdinand.
As a last major measure - after a legal dispute with the state regarding the assumption of costs - the facades of Glücksburg were extensively renovated from 2005.
The base area is a square with an edge length of almost 30 meters, consisting of three individual houses, each with its own floor plan and roof.
The palace chapel, with its east-facing altar wall, is the only room that was placed across the overall floor plan and is located in the east and middle house at the same time.
The courtyard side of the castle is also preceded by two bay-like stair towers, which form the only connection between the upper floors.
In 1768 the middle roof received the baroque ridge turret, the wall dormers removed in the 19th century were renewed from 1906 onwards.
The basement rooms have their own entrances so that staff or visitors to the palace chapel, which was later made public, did not have to enter the vestibule.
The green hall was always furnished in a very simple way, but the floor is remarkable, with its footplates which are made of Öland stone and show imprints of fossils in many places.
The church was originally furnished in the Renaissance style and still contains a pulpit altar and a baptism from the middle of the 17th century, both works by Claus Gabriel.
To the west of the chapel is the house crypt in which the last burial took place in 1811 and in which 38 members of the ducal family are buried.
The middle White Hall lacks the vaulted ceiling of its "red" counterpart, which makes it appear larger and deeper.
Like the castle itself, the buildings of the farm yard are also typical of the rural architecture of the Schleswig-Holstein nobility at the time of the Renaissance.
The outer bailey was partially destroyed in a fire in 1717, mainly the bakery and brewery that once bordered the fourth side of the courtyard facing the castle.
In addition to the actual main entrance to the castle area, the gatehouse was primarily used as a stable building and coach house .
The twelve-axis cavalier's house from 1685, facing west, was raised by one floor in the 18th century, and the curved gables of the attic were not added until 1856.
The baroque structure was largely retained, so that the framing avenues and the path system of the old garden have been preserved to this day.