But the most suggestive and resonant moments of this journey, in my view, were not the prayer in the mosque or other encounters with Islamic and Turkish authorities, but the meetings with Bartholomew I, patriarch of Constantinople and senior bishop in the world-wide communion of Orthodox Christians. I gather that romanticism about ecclesiastical matters is not fashionable among right-thinking Catholics nowadays, but you would need a heart of stone (and downright ignorance of history) to avoid being moved by their shared prayers and conversations.

To see these men together was to be reminded of vast realities about the past and future of the entire Christian movement. They were together in Istanbul as patriarchs descended from the one immense Christian community that flourished in the Latin and Greek parts of the late Roman empire, each contributing profound treasures of liturgy, devotion, theology and practical spirituality to the religious commonwealth. Whatever our differences, the churches of both Orthodox and Catholic traditions share a common heritage of unfathomable value.

Yet for all that, Benedict and Bartholomew could still not share Holy Communion in Istanbul, because of the division between East and West that began with the break-up of the empire in the fifth century and culminated in bitter schism nearly 1,000 years ago. The churches now face each other across a great gulf of history and culture, fraught with deep-rooted and understandable suspicions and animosities.

But for an instant, in the glow of mutual respect, kindly intentions and liturgical splendour that characterized the encounter, one could almost catch a glimpse of the charismatic unity promised by Christ to His church: not a grinding uniformity, but a gathering of diversities, a union of differences, all brought to glorious fulfilment in the one Lord. Then it was all over: A joint declaration was published, of the sort ecclesiastical figures always issue after such public meetings. Each man then returned to the practical realities of governing his respective Christian community, and the division of a millennium seemed as deep and unhealing as ever.

That divide between the Orthodox and Catholic Churches is indeed very real. On the face of it, the official positions of Rome and Constantinople on reunion seem to have changed discouragingly little since 1964, when Pope Paul VI and the Patriarch Athenagoras made history by meeting in Jerusalem. Yet if church dignitaries have changed little, the Holy Spirit has continued to move dramatically in the affairs of people and nations, transforming forever the context of all talk of East-West unity.

In 1964, after all, most Catholics were starkly divided from most Orthodox Christians by the Iron Curtain, as well as by specifically religious factors. The problems Christians faced were profoundly different, even though both sprang ultimately from the Enlightenment of the 18th century. Then, with the astonishing collapse of European communism the world of the Orthodox churches radically changed.

Now, some 15 years later, all of us who live on earth face the common, hugely potent forces of globalism and secularization at work in the universal capitalist environment. The implications of this new order for East-West religious dialogue can hardly be overestimated. Not since the zenith of Roman imperial power have all the world's Christians inhabited one world, with such strongly unified economic and communications systems. In this new global arrangement, the very terms East and West cease to have their old, rigid meanings, as all Christians are bound ever more closely.

The conference between Benedict and Bartholomew was a hopeful sign that the doors remain open between the churches, which now have the challenge of catching up with God as He changes the world according to His providential plan for us.

(Mays is a Toronto author and journalist.)