Schloss Heiligenberg

In 1811 the Heiligenberg — farmed again since 1769 after the secularisation of 1803 — passed to the Hessian court chamber councillor August Konrad Hofmann, who built an agricultural estate house at the foot of the later Marienberg between 1813 and 1816, possibly with input from the Darmstadt court architect Georg Moller. Hofmann sold the estate in 1827 to Wilhelmine, then Hereditary Grand Duchess of Hesse and by Rhine, who used it as a summer residence; once her husband Ludwig became Grand Duke on his father's death and greater funds came to her, she had Moller convert the farmstead into a Schloss from about 1831.

On 28 October 1851 Wilhelmine's third son, Alexander (1823–1888), entered a morganatic marriage with Countess Julia Hauke, a lady-in-waiting to his sister, Tsarina Maria Alexandrovna of Russia. From 1852 he lived mainly in Darmstadt or at Schloss Heiligenberg, at least when not on campaign, and from 1862 the couple carried out repeated rebuilding of the Schloss — continuing on and off until 1886 — apparently to designs Moller had drawn up in 1846, before his death. Alexander and Julia founded the house of Battenberg, whose English branch anglicised its name to Mountbatten during the First World War; their eldest daughter, Marie Karoline, born at Strasbourg in 1852, later recorded life on the Heiligenberg in her own memoirs. Princess Louise of Battenberg, Queen of Sweden from 1950 until her death in 1965, was born at the Schloss in 1889.

Wilhelmine's four children dedicated the Golden Cross on the hill to her memory in 1866. Alexander died in 1888 and Julia in 1895; the Battenberg mausoleum, completed beside the cross in 1894, was built for them. Thanks to the family's wide-ranging dynastic connections, the Schloss remained until 1914 a regular meeting point for the Russian Tsar and his family and for other kings, princes and diplomats.

In 1920 Alexander's son Prince Ludwig Alexander of Battenberg — Louis Mountbatten, 1st Marquess of Milford Haven, from 1917 — sold the Schloss to two investors, the Berlin privy councillor Dr Theodor Görges and his son-in-law Heinrich, Prince of Hohenleuben, having run into financial difficulty after his 1918 discharge from the Royal Navy. In the mid-1930s, allegedly to settle tax debts, ownership passed to the Hessian state, by then under Nazi control, which used the Schloss first as a training school for regional leaders of the Bund Deutscher Mädel and for home economics; it served until the end of the war as an auxiliary military hospital.

From 1946 to 1963 the Schloss held the Pädagogisches Institut Jugenheim, training primary and secondary teachers for Hesse after the institute was moved out of space-short Darmstadt at the end of 1945; the American occupying authorities pressed for it to relieve a teacher shortage and secure democratic teacher training. The institute closed in 1963 once the newly founded Hochschule für Erziehung in Frankfurt took over that role, and the Amt für Lehrerbildung, a regional education office, occupied the Schloss until 2011.

A foundation took over the Schloss in 2012 for the preservation of art and culture; the municipality of Seeheim-Jugenheim has since kept a register-office wedding room there, and the Gartensaal and courtyard are used for concerts and art exhibitions. Since 2014 the local 'Juremer Kerb' fair has opened at the Schloss, and in 2015 a Christmas market was held in the courtyard for the first time. It is listed as a cultural heritage monument in Hesse and is owned by the State of Hesse.