VI expanded the rite of the Jubilee year of 1500 by opening other doors in Saint Peter's Basilica, Basilica of Saint Mary Major and the Basilica of Saint Paul Outside the Walls. This jubilee year began on Christmas day and ended on the Feast of the Epiphany 1501. During the reign of Pope John VII the holy doors were opened every 50 years, reflecting the number of years attributed to the lifespan of Jesus Christ. This was later amended to 50 years in commemoration of the Hebrew custom of Jubilees and later changed to a centenary or at any time at the will of the reigning Pontiff. Between 1500 and 1974, the entrance portal was barricaded by a solid wall, not an actual door. The popes themselves began the ritual destruction of these walls followed by masons who completed the actual task demolishing it. This describes a rite that has nearly always supplied the principal subject depicted upon the long series of Jubilee medals issued by the numerous Popes who have opened and closed the holy door at the beginning and end of each Jubilee year. Each of the four basilicas has its own holy door. After closing the Holy Year on Christmas day 1950 Pope Pius XII replaced the wooden doors installed by Pope Benedict XIV in 1748, which had begun to fall into disrepair, with the 16-panelled bronze doors (modelled by Vico Consorti and cast by Ferdinando Marinelli Artistic Foundry) that are seen today. Symbolism In John 10:9, Jesus is quoted as saying, "I am the gate. Whoever enters through me will be saved." In Luke 11:9 is found, "And I tell you, ask and you will receive; seek and you will find; knock and the door will be opened to you." Revelations 3:20 says, "Behold, I stand at the door and knock. If anyone hears my voice and opens the door, (then) I will enter his house and dine with him, and he with me." Dom Albert Hammenstede O.S.B. noted that Porter was one of the minor orders. Herbert Thurston suggests that "the symbolism of this ceremony may also have been influenced by the old idea of seeking sanctuary". In the papal bull, Incarnationis mysterium of 29 November 1998, Pope John Paul II formally announced the Great Jubilee of 2000 saying that the Holy Door "evokes the passage from sin to grace". The Holy Door represents "a