The Bishop of London will lead the Church of England delegation for the Third European Ecumenical Assembly.
The historic city of Sibiu will host some 2000 delegates from churches across Europe to share their vision and hopes for renewal and unity in Europe.
Bishop Richard Chartres, who will be making a keynote speech at the Assembly, said: "The Assembly, which embraces every strand of Europe's Christian community, met first in Basle at the end of the 80s when the Berlin Wall was breached and it looked as though the Cold War was over. At the end of the 90s, with armed conflict in the Balkans and no sign of a holiday from history, the Assembly met for a second time in Graz, Austria.
"Now, for the first time, the venue is in a predominantly Orthodox country and one that has recently joined the EU. The theme will inevitably be the moral and spiritual direction of travel for Europe and the role which Europe's Christian Churches intend to play in the future."
The Assembly, organised by the Conference of European Churches and the Roman Catholic Bishops' Conferences in Europe, runs from 4-9 September.
Timi Dorgu, a student of international business at Warwick University and the youngest member of the Church of England delegation, said: "This is a fantastic opportunity to share my experiences as a young person in the Church of England and learn from those of people in other European churches, especially amid the changing face of European Christianity as a result of migration."
European identity, other faiths, migration, creation, justice and peace will be on the agenda, alongside questions of unity, spirituality and witness.
Delegates will share in prayer and worship from different traditions, discover the Christian heritage and hopes of Romania, a nation which looks forward to playing a full part in Europe, and set an agenda for common witness and action across Europe at a time of tremendous challenge.
"The work will go on before, during and well after Sibiu," said Canon Charles Hill of the Council for Christian Unity, who has been encouraging European groups in dioceses to engage with the Assembly's themes with partner churches in mainland Europe.
"Sibiu will give new impetus to the churches of Europe to raise their common profile and renew their mission to bring the light, hope and love of Jesus Christ to our continent," he said.
