In the Middle Ages, Glaadt was even more important than Jünkerath, which at that time was only a hut settlement. For this reason, a castle was built on this site in the 14th century by Count Dieterich von Schleiden.

The castle was besieged and conquered several times, mainly by the archbishops of Trier. In 1488, the Counts of Manderscheid-Blankenheim inherited the area through the Manderscheid partition. Due to dilapidation, the late medieval complex was demolished and rebuilt as a moated castle by Count Arnold in 1605 - 1610. The entrance with a drawbridge was located in the western part.

From 1694 - 1705, Count Salentin Ernst spent the last years of his life in the castle, where he also died.

In 1726 - 1735, Count Franz Georg had a major renovation carried out and converted the castle into a palace complex. The castle has a square ground plan and consisted of two storeys, high round-arched windows adorned the west wing. In the inner courtyard there is a fountain and a paving of quartz stones with ornaments.

Next to the castle stood a mill, a bakehouse and a brewery, as well as a riding arena and gardens with a baroque ambience. In the area around the ruins, the former moat and the approximate extent of the complex, indicated by the remains of the walls, are still clearly recognisable.

Two years after its completion, the castle burnt down and has remained a ruin ever since. According to legend, the fire was caused by a bolt of lightning, as a punishment from God, since it is said that God was blasphemed during the inauguration ceremony.

In the 1970s and 1980s, the ruins were uncovered and restored with the help of many volunteers and associations.