Today, Pope Francis will open the original Holy Door at St Peter's Basilica in Rome, the first time it has been opened since the turn of the century, to mark the official start of a year laden with symbolism for Catholics across the world:The Jubilee Year of Mercy.

So what does it mean? The clue to the aim of the Year of Mercy is in its name: a time for the Church itself and for Catholics everywhere to show mercy and compassion, in thought and in deed, and focus on forgiveness, reconciliation and doing good in concrete ways for the needy and those on the margins of society.

The crossing of the threshold of a Holy Door is a sign of spiritual renewal, and the passage from sin to grace.

Pope Francis has long signalled his wish to change the Church's approach from condemnation of wrongdoing to a Church more forgiving of its flock, and more understanding of the difficulties faced by believers today.

This extraordinary jubilee year is a practical way of giving expression to that wish, and creating a Church that is a "field hospital", healing and binding the wounds of its flock.

Announcing the extraordinary jubilee this March, the Pope said: "The greater the sin, the greater the love the Church must express," writing that the Holy Door is a "Door of Mercy, through which anyone who enters will experience the love of God who consoles, pardons and instils hope."

The Pope has also made clear he wants this jubilee to open a year of "fervent dialogue" between Christians, Muslims and Jews, so that all who believe in a merciful God show more mercy towards one another, driving out violence, disrespect and discrimination.

Jubilee years are rooted in the Old Testament tradition of freeing slaves and prisoners once every 50 years, a concept that died out within Judaism but was taken up by Pope Boniface VIII for the Catholic Church in 1300.

The last Jubilee was called by St John Paul II to mark the millennium, and this Holy Year of Mercy starts on the Feast of the Immaculate Conception on 8 December 2015 and will end on the Feast of Christ the King on 20 November 2016

A PRAYER FOR THE

JUBILEE OF MERCY

BY POPE FRANCIS

Lord Jesus Christ,

you have taught us to be merciful like the heavenly Father,

and have told us that whoever sees you sees Him.

Show us your face and we will be saved.

Your loving gaze freed Zacchaeus and Matthew from being enslaved by money;

the adulteress and Magdalene from seeking happiness only in created things;

made Peter weep after his betrayal,

and assured Paradise to the repentant thief.

Let us hear, as if addressed to each one of us,

the words that you spoke to the Samaritan woman:

“If you knew the gift of God!”

You are the visible face of the invisible Father,

of the God who manifests his power above all by forgiveness and mercy:

let the Church be your visible face in the world, its Lord risen and glorified.

You willed that your ministers would also be clothed in weakness

in order that they may feel compassion for those in ignorance and error:

let everyone who approaches them feel sought after, loved, and forgiven by God.

Send your Spirit and consecrate every one of us with its anointing,

so that the Jubilee of Mercy may be a year of grace from the Lord,

and your Church, with renewed enthusiasm, may bring good news to the poor,

proclaim liberty to captives and the oppressed,

and restore sight to the blind.

We ask this of you, Lord Jesus, 

through the intercession of Mary, Mother of Mercy;

you who live and reign with the Father 

and the Holy Spirit for ever and ever.

Amen.