The entrance to Prague Castle from the north side, from the Powder Bridge, leads through the Pacassi Gate and a passageway that hides the remains of a Renaissance gate made of massive, roughly worked blocks. On both sides of the gate were stables in the second half of the 16th century, during the reign of Emperor Rudolf II. In the 20th century, these stables were converted into exhibition spaces. The Picture Gallery of Prague Castle was built in one part, and the Imperial Stables was adapted in the other wing for art exhibitions in 1993.