There are many tales of ghosts at the palace. One of them is the "Grå Gubben" (the Old Grey Man) who according to tradition lives in the cellar ruins of the old Tre Kronor Castle. He is considered to be a kind of guarding spirit for the palace and he is able to predict the future. According to other legends it is no other than Birger Jarl standing guard. He is supposed to have appeared for Nicodemus Tessin the Younger, to tell him that he would not live to see the palace completed.