The so-called 'foreign minister' of the Russian Orthodox Church's Moscow Patriarchate is on the move.
Last week, he gave a notable and bold speech in London organised by the Russian Embassy, before travelling to Rome to meet with Pope Francis, who raised the thorny issues of Ukraine and religious freedom in Russia, and, more ceremonially, Francis' predecessor Pope Benedict XVI.
What's he up to, and what do his various pronouncements mean for relations between Russia and the West?
First, the London speech.
Addressing a mix of diplomats, politicians, entrepreneurs and religious figures, Metropolitan Hilarion (Alfeev) claimed that Christianity is dying out in Europe and being replaced with 'the monopoly of the secular idea'.
He said: '[The] monopoly of the secular idea has affirmed itself in contemporary Europe. Its manifestation is the discrimination of religious vision in the social sphere.'
Here, the Metropolitan is likely referring to the social liberalism on sexuality and life issues that he sees as prevalent in the West. The social conservatism of the Russian Orthodox Church has been a pressure point when it comes to ecumenical relations, and the Orthodox Church is known frequently to view the social liberalism of Western churches as part of the problem rather than part of the solution.
He added: 'Other peoples will live in Europe in the future, with other faiths, other cultures, and other paradigms of values.' The cause, Hilarion said, was liberalism, or 'the realisation of human rights and fundamental freedoms in all fields of civil, economic, political, social and cultural life'.
Hilarion appealed for this to be countered by unity among the Churches. 'In the current conditions of oppression by power groups that propose ideas incompatible with the traditional views of Christian morality, it is indispensable to unite Church efforts to counter these processes, to act together in the field of information and legal support, and in the propagation of common Christian values at all levels,' he said.
'Christians in Europe must strive to defend their values on which the continent has been built for centuries, and listen to the lamentations and sufferings of Christians from all over the globe.'
Dr James Rodgers, the leader of International Journalism Studies at City, University of London and a former BBC Moscow correspondent, sets out the crucial context. 'For the whole of its post-Soviet history, Russia has been seeking to fill the ideological void left by the collapse of Communism. An important element of that has been emphasising a uniquely Russian identity. The Orthodox Church has been an indispensable part of that,' Rodgers tells Christian Today.
The respected academic, who was in Moscow 1991-93 for Reuters TV, and from 1998-2000 and 2006-2009 for the BBC, adds: 'In consequence, opinion polls have consistently suggested that the vast majority of the Russian population identify themselves as Orthodox Christian – even if church attendance, with the exception of major religious holidays, remains relatively low. The Church preaches a message of socially conservative values. This translates on the international stage to Russia portraying itself as the guardian of what it sees as traditional Christian beliefs in the face of growing secularism, and Metropolitan Hilarion's remarks can be seen as part of that.'
Linked to his concerns over the decline of Christianity in Europe, the Metropolitan also seems preoccupied with immigration.
He cited among challenges 'changing the ethical and religious landscape of Europe' the migration crisis seen as the most serious since the end of World War II and caused by 'military conflicts and economic problems in the Middle East'.
The Russian prelate cited the official data of the Frontex agency, according to which 1.8 million migrants arrived in the EU alone; according to the UN, the number of migrants in European countries increased from 49.3 million in 2000 to 76.1 million in 2015.
He also referred to figures showing that 1.3 per cent of the adult population (66 million people) are planning to move definitively from their country mainly towards to the most affluent European nations.
Though he doesn't mention it explicitly, the Metropolitan is surely talking here talking about Muslims.
On this area at least, according to the Catholic blogger Fr Alexander Lucie-Smith, he is correct.
'The truth is that Hilarion is right: if we admit large numbers of migrants from North Africa and the Middle East, then the character of Europe will change,' Lucie-Smith wrote on the Catholic Herald website. 'The only question is how will it change, and whether this change will be a good or a bad thing... Metropolitan Hilarion's speech is certainly interesting, and in many ways challenging. On many topics, he hits the nail on the head, but in practical terms, where do we go from here? An honest discussion about Ukraine would be a good place to start.'
Such a discussion, albeit a brief one, took place between Pope Francis and the Metropolitan last Tuesday, when the two men met so that, officially, the latter could thank the Pope for the recent loan of the relics of the 4th century Saint Nicholas of Myra, which were taken from the southern Italian city of Bari to Moscow and St Petersburg and drew huge crowds of Orthodox pilgrims during the two month loan period.
According to Vatican Radio, they discussed 'ongoing tensions in Ukraine', though no details were given, as well as joint efforts to support Christians in the Middle East and religious freedom in Russia. On the latter point, many are concerned at what appears to be a major crackdown in Russia on a host of religious freedoms, with new laws restricting any kind of sharing of the faith anywhere except official churches. The 2016 Yarovaya Law extends the legal restrictions against extremism to include evangelism by minority faiths.
Yet on religious freedom, Metropolitan Hilarion reportedly said that the concerns of some journalists 'in my view, are ungrounded'. He added that Jehovah's Witnesses have been prohibited from activities recently, since they are considered 'not as a Christian Church, but as a sect'.
The Metropolitan also exchanged gifts with Pope Emeritus Benedict XVI.
According to Pravmir, Metropolitan Hilarion told him about the construction of new churches and monasteries, the establishment of theological faculties in secular universities, and the Church's publishing and educational activities.
There is no doubt that Metropolitan Hilarion has been on a diplomatic mission in recent days.
One man who recently had a one-to-one with Metropolitan Hilarion is Nicholas Cobb, the chairman of the Westminster-Russia Forum.
'Having met the Metropolitan I was impressed by his vision for interfaith dialogue to overcome socio-political factors,' Cobb tells Christian Today.
In ecumenical circles, he is known as sometimes being a thorn in the side of closer ties. Yet some of the Metropolitan's message, to London and to the Popes, is undeniably accurate.
'When mentioning the decline in Christian membership here in Western Europe and the rise of Orthodoxy in the East he is absolutely right...The overriding impression I took from meeting him was the need for interfaith dialogue to promote areas of mutual interest.
'From combating social ills to fostering relations between those of Europe and Russia, it is clear that cooperation between the faiths is a key tool to deal with socio-political issues.'
In the end, As Rodgers says, the Russian Orthodox Church is an important part of Russia seeking to assert its identity under President Vladimir Putin, who appears to be forging ever closer ties to the Church.
And, doubtless, the Metropolitan Hilarion is in turn an important part of that attempted boost. He is one to watch.
