„Haus Carstanjen“ in the Plittersdorf water meadow has a long history. Originally the manor was in hands of King Arnulf von Kärnten, regent of the Rhineland between 887-899, who gave it to monks from Gandersheim that settled here. In 1197, Ceasarius, famous prior of the Cistercian Abbey in Heisterbach bought the manor then known as „Auerhof“.
After the French Revolution (1789-1799) a process called „secularization“ began, that means the confiscation of church properties and lands by the secular German states in 1803. „Auerhof“ was also confiscated and allocated to the commandant’s office of Poppelsdorf.
When the Rhineland became a part of Preussen in 1816, banker Johann Abraham Anton Schaaffhausen bought „Auerhof“.
After him his daughter Sibylle Mertens-Schaaffhausen, married to Louis Mertens – the successor of her father in his bank – resided the manor. At that period „Auerhof“ was the place to be of the local high society. Poetesses Annette von Droste-Hülshoff and Adele Schopenhauer as well as writers Anna Jameson, an early feminist born in Ireland, and Henriette Paalzow were frequent visitors of the estate.
After she had to abandon her heritage in favour of her children, Sibylle moved to Genua and lateron to Rome, where she died in October 1857.
Next, family Suermondt of Aachen acquired possession of „Auerhof“. They sold it to business man Andreas Solf.
In 1882 Adolf von Carstanjen became the new owner of the manor, which since then is known as „Haus Carstanjen“. Since then the property was not longer used for agricultural but for representative purposes only.
In 1892 „Haus Carstanjen“ was transformed into a gothic castle by the architects Hartel & Neckelmann and Josef Kleefisch (from 1895).
During the nazi-regime the castle hosted a military academy. After World War II „Haus Carstanjen“ was occupied by the staff of John McCloy, who directed from this place the reconstruction of Germany, the realisation of the Marshall Plan, as well as the erection of the American Embassy in the district of Rüngsdorf/Mehlem.
Since November 1957 the Ministry for Federal property, renamed as Federal Treasury in 1961, resided the vacant building. The Ministry was dissolved in 1969, some of its functions being assigned to the Federal Ministry of Finance, which also took over the former official premises of that authority, „Haus Carstanjen“ in Plittersdorf.
In 1967/1968, in order to create place for a new office-building for the Federal Ministry of Finance, which was located since the early fifthies at Bonn-Graurheindorf, the stables, barns and the greenhouse still standing up were demolished by architect professor Sepp Ruf.
After the reunification of Germany in 1990 the Ministry moved to Berlin. In June 1996 the UN Climate Change Secretariat came from it’s previous location Geneva/Switzerland to „Haus Carstanjen“ at Plittersdorf on Rhine, where it is still hosted today.
(First publication: May 1, 2007)