We have entered the week of Prayer for Christian Unity and thus today at Mass we prayed the traditional prayer that our “separated brethren” may return to “the one true fold.” What a potent mixture of theology and pain these phrases conjure up: yes, those members of the many Protestant churches are separated from the Church but they are also our “brethren”, not least in their fervour for fundamental aspects of the Christian faith; and it is also true that Christ intended one shepherd and one flock – the “true fold” of the Church. That this can cause anguish is not in doubt; witness the spiritual travails of Blessed John Henry Newman before his conversion. But its resolution, sometimes referred to jocularly as “swimming the Tiber”, can also bring peace that the world cannot give.