In 1497, the gate building with the Idstein castle gate was built under Philip I. In the Middle Ages, the impressive portal was the only access to Idstein Castle from the town, with the aim of protecting it against intruders. Due to its representative design, the Idstein Castle Gate served as the venue for the reception of the Roman-German King and later Emperor, Maximilian I, during his visit to Idstein in 1502. The castle gate was used, among other things, for the land scribe’s office, the bookkeeping department and as the court chamber. In addition, the guards and the prison with torture chamber were later housed here. The prisoners had their own entrance via the side staircase.