The remains of the Castle can be visited
Homburg Castle

Homburg Castle Ruin, a High Medieval architectural site, is situated above Stahringen, a district of Radolfzell am Bodensee. As the former residence of the Lords of Homburg, it gives a glimpse into past eras.
History+
The origins of Homburg date back to the 11th century, when the Lords of Homburg, once ministerials of the Bishop of Constance, erected a ring wall on glacial gravel remnants. In 1499, during the Swiss War, the castle was plundered, burned down, and its inhabitants expelled. Reconstruction and enlargement took place in 1502. Wolf von Homburg sold the lordship in 1565 to his son-in-law Hans Konrad von Bodman. After almost 50 years in the possession of the Lords of Bodman, the village and castle passed to the Benedictine monastery of St. Gallen in 1614.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://schloesserrundschau.de/bawue/schloesser/konstanz23.html
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: 47.7921, 8.9663