Schloss Röttgen

Röttgen's roots reach far back: a knightly seat arose here between the 9th and 13th centuries, possibly a water-protected structure — the grounds sit in the hollow of a former arm of the Rhine. In 1402 Johann Kreuwel von Gimborn was enfeoffed with the "Hoff zome Roetgine"; like the nearby place-name Rath, the name is thought to derive from woodland clearing.

Over the centuries the estate passed by inheritance through the Bourscheidt and Harff families before falling in 1660 to Bertram von Gymnich, whose wife Maria von Harff brought Röttgen into the marriage. Little is known of the buildings of that era beyond a house chapel. Decades of inheritance disputes followed, some of them violent, carried all the way to the Imperial Chamber Court and dragging on until at least 1704.

Ownership remained contested afterwards: following the death of the canon Franz Dietrich Beißel von Gymnich in 1706, his brother sold the estate to the Cologne painter Johannes Justus Borchers, who was driven out in 1709. Only the imperial Aulic Council in Vienna restored the property to him. In 1776 a French army survey recorded a size of 150 Morgen (37.5 hectares). In 1790 Baron Kornelius Josef Geyr von Schweppenburg acquired the estate at public auction; he had the old knightly manor demolished, though a farmhouse remained.

The new tenant, and from late 1918 the owner, was Peter Mülhens, proprietor of the eau-de-Cologne firm 4711. In 1924 he founded the Röttgen thoroughbred stud. The Cologne architect Ludwig Paffendorf designed the stud buildings in a German Renaissance idiom, and the entire estate was enclosed "after the Irish model" by a wall about eight kilometres long and two metres high, known as Mülhens' Wall. Further buildings went up into the 1930s. In 1927 Mülhens also acquired the Leidenhausen estate and had a 2,100-metre training track laid out there for the racehorses.

During the Second World War around 1,000 high-explosive bombs fell on the grounds without seriously damaging the buildings; as late as 1975, ten aerial bombs were found and defused. Peter Mülhens died on 5 August 1945.

Many structures on the grounds are listed monuments — the castle itself, the wall, the gatehouse on the Mauspfad, the sawmill, the estate office, the stable buildings and the observation tower, together with the surrounding woodland and garden. In 1998 Cologne's monuments authority praised Schloss Röttgen as a largely original, integrated work of art of European significance.

The castle and its estate — now about two square kilometres — are not open to the public. Under the forest law that came into force in North Rhine-Westphalia in 1970, which in principle opened woodlands for recreation, the state agriculture minister tried in vain to have the wall removed; the owners invoked an exemption for commercially used woodland — opening the wall would call the stud itself into question. One curious detail: so that the racehorses can safely cross the Hirschgraben to the training track, a hand-operated traffic light was installed specifically for that purpose.