The remains of the Castle can be visited
Welschbillig Castle (Ruin)

The Welschbillig Ruin, a moated castle, is located in the municipality of the same name in Rhineland-Palatinate. It was built on the foundations of a Roman villa rustica and still shows traces of its defensive past today.
History+
As early as the 12th century, a small castle complex was built on this site, resting on the remains of a Roman villa from the 2nd to 4th centuries. Between 1242 and 1299, the moated castle underwent massive reinforcement under Archbishop Arnold II of Isenburg and was subsequently expanded into a regional castle by his successors.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 49.8533, 6.5687