The Archbishop of Canterbury has hit out at the "feverish advertising culture" that fuels "unreal and disproportionate desires" when he joined the Pope for evening prayer in Rome.
Dr Rowan Williams and Pope Benedict XVI together led the service at the Church of San Gregorio Magno al Celio as part of the Archbishop's visit to the Italian capital.
Both church leaders delivered homilies, with Dr Williams saying: "In recent years, we have seen developing a vastly sophisticated system of unreality, created and sustained by acquisitiveness, a set of economic habits in which the needs of actual human beings seem to be almost entirely obscured."
He continued: "We are familiar with a feverish advertising culture in which we are persuaded to develop unreal and disproportionate desires. We are all - Christians and their pastors included - in need of the discipline that purges our vision and restores to us some sense of the truth of our world, even if that can produce the 'torment' of knowing more clearly how much people suffer and how little we can do for them by our unaided labours."
Before travelling to San Gregorio to join the resident monastic community there for Vespers, or evening prayer, the Archbishop and Pope held a private meeting.
At the church, both lit candles in the Chapel of St Gregory the Great.
Dr Williams was invited to Rome to take part in the celebrations of the 1,000th anniversary of the Camaldolese (Benedictine) monastic family.
His joint appearance with the Pope at the church marked its close connection to the Church of England and the Anglican Communion, and the Archbishop used the occasion to hail the "communion" shared by the Catholic Church and his own.
The Vespers (evening prayers) are the third time in recent decades that the Bishop of Rome and the Archbishop of Canterbury have shared a liturgical celebration in the historic setting of San Gregorio. In September 1989 Archbishop Robert Runcie joined John Paul II, and in December 1996 Archbishop George Carey lead prayers with the former Pope.
Dr Williams recalled the 1989 meeting in his homily, when the then Pope and Archbishop had "characterised the communion that our two churches share" as "certain yet imperfect".
He went on: "'Certain' because of the shared ecclesial vision to which both our communions are committed as being the character of the Church both one and particular... And 'yet imperfect' because of the limit of our vision, a deficit in the depth of our hope and patience."