The former Benedictine provostry Oberpleis in Königswinter is a ground monument. This was decided by the Münster Higher Administrative Court (OVG), which dealt for the first time with the category of presumed ground monument, which was newly introduced by the state legislature in 2022 (Ref.: 10 A 2200/24 of 19 May 2026).

With this new category, the legislator in NRW is addressing a well-known problem in the preservation of archaeological monuments: as archaeological monuments are often completely buried in the ground, it is necessary to dig to find out whether they really exist. However, there is a risk of damaging or destroying the archaeological monument, particularly in the case of improper excavations.

In this particular case, the district government of Cologne had arranged for the land of the former Benedictine monastery to be entered as a monument on the Königswinter heritage list. An owner of two affected plots of land filed a complaint against this. He argued that it had not been proven with certainty whether archaeological features were actually present in the ground. The introduction of the presumed ground monument into the Monument Protection Act was unconstitutional because it disproportionately curtailed the rights of property owners. The OVG Münster now took a different view and confirmed the new category; the Administrative Court of Cologne had also already dismissed the complaint.

For „suspected archaeological monuments“ according to the North Rhine-Westphalia Monument Protection Act, it is sufficient if there are concrete, scientifically substantiated indications. A probability bordering on certainty that a ground monument is present in the affected area is no longer necessary. In the opinion of the court, there is sufficient scientific evidence for the existence of such archaeological features in the ground in the present case. The court also does not share the plaintiff's constitutional concerns. According to the court's press release, the regulation is proportionate in view of the typically low maintenance costs for archaeological monuments in contrast to architectural monuments. Furthermore, there is a public interest in the preservation of the ground monument, as the Probstei Oberpleis is one of the „important testimonies to medieval and modern monastic life in the Rhineland“.

„Treating suspected archaeological monuments as existing archaeological monuments is also a very far-reaching approach compared to other state monument protection laws,“ says Rechtsanwalt Tobias Roß. The monument protection laws of the other federal states have so far partly provided for other precautionary instruments such as excavation protection areas and obligations to report finds. The fact that the OVG has now confirmed this approach is also likely to be closely followed in other federal states, says Roß.