Portrait of Alexander VI
The institution of a specific ritual for opening and closing the Holy Door dates back to the Jubilee of 1500 and Pope Alexander VI (Rodrigo Borgia). The ceremony remained unchanged until 1975, when Paul VI simplified several aspects.
N. F. Mathey, Alexander VI pont. max., in: Alexander Gordon, La vie du Pape Alexandre VI. et de son fils Cesar Borgia..., vol. I, Amsterdam 1751