As it was with his pontifical predecessor, the need to move toward the restoration of Christian unity is central to how Benedict XVI sees his pontificate. Writing in the 1980s, then-Cardinal Joseph Ratzinger argued that an important part of that work will be the renewed attention to the Church Fathers, representing as they do the common ancestors of the Eastern Church (which is most especially devoted to the Church Fathers) as well as the Catholic, Protestant and Reformed Churches of West.
When, Cardinal Ratzinger asked, did the patristic age end? Put slightly differently, the question is: what is the decisive date of the division between the Eastern and Western Churches? In trying to answer this question, he made a most remarkable observation:
… the end of Fourth Ecumenical Council does indeed represent a certain watershed. Nevertheless, the era of Church councils approved by both East and West persisted; the unity of faith and communio continued to express itself in the unity of common theological thought. The year 1054, on the other hand, is too peripheral and incidental a date to be meaningful as a reference point; the event of that year only made clear outwardly what had long existed in fact: that East and West spoke different languages, thought in different theologies – that, in other words, there still existed particular theologies but no “ecumenical theology” such as had existed in the time of the Fathers. We would have to say, then, that the patristic age ended with the changed intellectual climate marked by the Migrations and by the hostile spread of Islam; as an outward sign of the latter, we can point to the pope’s turning to the Carolingian Empire, by which the old ecumenism was finally destroyed and – together with the creation of the church-state – the new self-understanding of the West, the fundamental constellation of the Middle Ages, was created.Only lately have we begun to reckon with the persistent historical impact on Christianity and the cultures it nourished of “the hostile spread of Islam.” That Islamic hostility might have contributed to the most significant division within Christianity is quite remarkable. Perhaps we can hope, however, that the current manifestation of this hostility will contribute to the cause of Christian unity.