The cafe, open to the public, is part of the premises of the Royal College of Surgeons of Edinburgh, an area becoming known as Surgeons' Quarter. 1505 is the year of the foundation of the College.
NT2673 : Holyrood Why not just look at the clock I hear someone asking. ;)
A. Because it was traditionally kept five minutes fast to encourage travellers to be on time for their (North British) trains at nearby Waverley station.