Returned to Knaresborough Castle this morning as the museum and keep tour were closed on Mondays. Met an absolutely brilliant young lady working in the museum who had a wealth of knowledge concerning the castle. Found out the sally port I noticed yesterday was constructed the same time as the King's Tower in the late thirteenth century. Interestingly, it is large enough for horses to pass through it. Also, I found out there were actually two other sally ports on the grounds (only large enough for people).
I didn't find out the museum worker's name, but many thanks to her nonetheless.
We had a great look around the King's Tower. Of particular interest was the cellar of the keep, which was used as a storeroom for victuals in the early 14th century. Later, it became a dungeon when the courtroom was established on the castle grounds.