The King referenced a personal "historic moment" as he reflected on the year in his annual Christmas message.
Charles, 77, and his wife, Queen Camilla, 78, visited the Vatican in October, where he became the first monarch since the Reformation to pray alongside the Pope in a public service.
His Majesty and Pope Leo XIV made history in what was seen as a symbolic moment of unity for Anglicans and Roman Catholics across the globe.
The King opened his speech by saying: "A few weeks ago, The Queen and I were delighted to make a State Visit to the Vatican where we prayed with Pope Leo in a historic moment of spiritual unity. Together, we celebrated the Jubilee theme, 'Pilgrims of Hope'."
He continued: "Pilgrimage is a word less used today, but it has particular significance for our modern world, and especially at Christmas. It is about journeying forward, into the future, while also journeying back to remember the past and learn from its lessons."
The broadcast was pre-recorded by the King at the Lady Chapel at Westminster Abbey – an apt location given its long history as a site of pilgrimage for those paying homage at the tomb of Edward the Confessor, whose shrine lies at the heart of the abbey built in the King’s honour.
Edward, who reigned for 24 years before dying in 1066, was said to be a monk-like monarch believed to have the power to heal and was canonised by Pope Alexander III in 1161 – with his tomb attracting pilgrims over the centuries.
It's the second time that Charles has opted to deliver his festive message outside a royal residence, having recorded last year's at the Fitzrovia Chapel in central London.
"Courage and sacrifice"
The monarch also paid tribute to war veterans as he referenced the 80th anniversaries of VE and VJ Day earlier this year, during which the royals played a key role in commemorations.
"The end of the Second World War is now remembered by fewer and fewer of us, as the years pass," the King said. "But the courage and sacrifice of our servicemen and women, and the way communities came together in the face of such great challenge, carry a timeless message for us all. These are the values which have shaped our country and the Commonwealth."
He added: "As we hear of division, both at home and abroad, they are the values of which we must never lose sight. For instance, it is impossible not to be deeply moved by the ages of the fallen – as the gravestones in our War Cemeteries remind us. The young people who fought and helped save us from defeat in both World Wars were often only 18, 19, or 20 years of age."
"Future more hopeful"
The King, who has long engaged with leaders of different faiths, also spoke of common values between communities, saying: "To this day, in times of uncertainty, these ways of living are treasured by all the great Faiths and provide us with deep wells of hope: of resilience in the face of adversity; peace through forgiveness; simply getting to know our neighbours and, by showing respect to one another, creating new friendships."
He later added: "As I meet people of different faiths, I find it enormously encouraging to hear how much we have in common; a shared longing for peace and a deep respect for all life. If we can find time in our journey through life to think on these virtues we can all make the future more hopeful."
The King's Christmas message in full
A few weeks ago, the Queen and I were delighted to make a State Visit to the Vatican where we prayed with Pope Leo in a historic moment of spiritual unity. Together, we celebrated the Jubilee theme, "Pilgrims of Hope".
Pilgrimage is a word less used today, but it has particular significance for our modern world, and especially at Christmas. It is about journeying forward, into the future, while also journeying back to remember the past and learn from its lessons.
We did this during the summer, as we celebrated the 80th Anniversaries of VE and VJ Day. The end of the Second World War is now remembered by fewer and fewer of us, as the years pass. But the courage and sacrifice of our servicemen and women, and the way communities came together in the face of such great challenge, carry a timeless message for us all. These are the values which have shaped our country and the Commonwealth.
As we hear of division, both at home and abroad, they are the values of which we must never lose sight. For instance, it is impossible not to be deeply moved by the ages of the fallen – as the gravestones in our War Cemeteries remind us. The young people who fought and helped save us from defeat in both World Wars were often only 18, 19, or 20 years of age.
Journeying is a constant theme of the Christmas Story. The Holy Family made a journey to Bethlehem and arrived homeless without proper shelter. The Wise Men made a pilgrimage from the East to worship at the cradle of Christ; and the Shepherds journeyed from field to town in search of Jesus, the Saviour of the World. In each case, they journeyed with others; and relied on the companionship and kindness of others. Through physical and mental challenge, they found an inner strength.
To this day, in times of uncertainty, these ways of living are treasured by all the great Faiths and provide us with deep wells of hope: of resilience in the face of adversity; peace through forgiveness; simply getting to know our neighbours and, by showing respect to one another, creating new friendships.
Indeed, as our world seems to spin ever faster, our journeying may pause, to quieten our minds - in T.S. Eliot's words "At the still point of the turning world" - and allow our souls to renew. In this, with the great diversity of our communities, we can find the strength to ensure that right triumphs over wrong. It seems to me that we need to cherish the values of compassion and reconciliation; the way Our Lord lived and died.
This year, I have heard so many examples of this, both here and abroad. These stories of the triumph of courage over adversity give me hope, from our venerable military veterans to selfless humanitarian workers in this century's most dangerous conflict zones; to the ways in which individuals and communities display spontaneous bravery, instinctively placing themselves in harm’s way to defend others.
As I meet people of different faiths, I find it enormously encouraging to hear how much we have in common; a shared longing for peace and a deep respect for all life. If we can find time in our journey through life to think on these virtues we can all make the future more hopeful. Of course, the greatest pilgrimage of all is the journey we celebrate today – the story of the One who 'came down to Earth from Heaven', 'whose shelter was a stable' and who shared his life with 'the poor and lowly'.
It was a pilgrimage with a purpose, heralded by Angels, that there should be peace on Earth. That prayer for peace and reconciliation – for "doing to others as we would have them do to us" – which rang out over the fields near Bethlehem more than two thousand years ago, still reverberates from there and around the world today. It is a prayer for our times, and our communities too, as we journey through our lives.
So, with these words and my whole heart, I wish you all a most peaceful and very happy Christmas.