Originally Denklingen seems to have been the seat of the old Grafschaft Sayn court and there was already a castle on the site in the 14th century belonging to the Duke of Berg.

On 23 February 1413, Johann von Gimborn was granted possession of Denklingen for life by Duke Adolf of Berg together with the people of the parish Drolshagen.

A document dated 1 September 1433, created when Duke Adolf formed an alliance with the landgrave Ludwig I of Hessen, directs that among other things Denklingen became an open house, "Unserem Slosse".

On 2 December a ceremony when the new subjects declared their homage took place near Heisterstock bei Winterberg (Nümbrecht municipality) in the open air.

The nobility of the new Berg lands were ordered on 11 March 1605 to take tribute to the castle at Denklingen and swear an oath of allegiance to the duke as lord.