Jewish tradition inspired the Catholic Church to start celebrating the jubilee. Jewish people celebrate a holy year every half century. The Catholic tradition was started in the year 1300 by Pope Boniface VIII.
A Holy Year is a general forgiveness, open to all. It is a special proposal to approach God and others. There are ordinary jubilees and extraordinary jubilees.
Since 1475, the ordinary jubilee is celebrated once every 25 years. The Pope convenes extraordinary ones on special occasions.
Until now, there have been 24 ordinary jubilees and four extraordinary. The Jubilee of Mercy, convened by Pope Francis, will be the fifth. The last extraordinary was imposed by John Paul II in 1983. John Paul II also imposed the last ordinary one, the Jubilee of the Year 2000.
The first rite is the opening of the Holy Door. It is only opened during a jubilee year. It symbolizes the extraordinary way that Catholics can open themselves up to their faith.