A ring has long been seen as a sign of a bond, of a promise to be honoured, and sometimes as a sign of authority. So when Pope Paul VI took off his papal ring and gave it to Michael Ramsey, the then Archbishop of Canterbury, during his visit to Rome in 1966, it was rich with meaning. With that gesture the successor to Peter reached out to the Church of England, helping to overcome centuries of tension and suspicion that had begun with Henry VIII’s break with Rome.

Ever since, archbishops of Canterbury have worn that same ring whenever they visit Rome and meet the Pope, and Justin Welby will do so when he sees Pope Francis this week. His trip will commemorate that historic encounter between Ramsey and Paul VI as well as celebrate 50 years of the Anglican Centre in the city. In that time individuals have played their part in mending relations. Benedict XVI and Rowan Williams were both intellectuals who enjoyed theological dialogue together; Francis and Justin Welby have focused more on common Christian witness, sharing, for example, a deep concern for the dispossessed, including refugees.