Pope John Paul II's Encyclical Ut Unum Sint, published in 1995, was immediately recognized as a document of fundamental importance for ecumenism. John Paul II clearly and unequivocally renewed the Roman Catholic Church's commitment to the ecumenical movement and invited leaders and theologians of other churches to engage with the Roman Catholic Church in patient and fraternal dialogue on the issue of the Petrine offices. A decade later this lecture reviews official Anglican responses to the Pope's initiative and sets out issues which Anglicans need to address and explore. Pope John Paul II's Encyclical Ut Unum Sint, published in 1995, was immediately recognized as a document of fundamental importance for ecumenism. John Paul II clearly and unequivocally renewed the Roman Catholic Church's commitment to the ecumenical movement and invited leaders and theologians of other churches to engage with the Roman Catholic Church in patient and fraternal dialogue on the issue of the Petrine offices. A decade later this lecture reviews official Anglican responses to the Pope's initiative and sets out issues which Anglicans need to address and explore.