Landsfort Herle was a fortification with moat. It was probably built by the counts van Ahr-Hochstaden (also referd to as Here van Are). The name Landsfort (‘fort of the land’) comes from the fact that the fortification come under the responsibility of the land. In the 13th century Heerlen, and thus also Landsfort Herle, come in to the possession of the Dukes of Brabant, the Landsfort was (re)built by the Dukes of Brabant in 1244.
The wall is believed to be one of the oldest still recognisable in the Netherlands, part is now being excavated. A marquette of the fort was constructed from a map form 1787 found while the Pancratiuskerk was heavily reconstructed in the 1960s. The fort had three gates and had two towers (the bell tower of the church and the Schelmentoren, both with 2 metre thick walls).
In the roof of the church were little rooms for the inhabitants of Heerlen to take shelter in case of hostilities, unfortunately these rooms were destroyed when a, supposedly German, bomb hit the church at New Year's Eve 1944/1945.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.