Like all veteran journalists who cover global religion news, Robert Moynihan of "Inside the Vatican" is used to getting interesting emails from sources in interesting places.

Normally, Moynihan asks the questions. But that wasn't the case in 2006 when he heard from Russian composer Hilarion Alfeyev, who was completing a new Passion According to St. Matthew, based on scripture and prayers from the Orthodox Divine Liturgy.

It's crucial to know that, in 2006, this composer was already a Russian Orthodox bishop. Today he is known as Metropolitan Hilarion and, as chair of his church's Department of External Church Relations, he has long been a key player in behind-the-scenes talks seeking a meeting between the pope of Rome and the patriarch of Moscow.

In that email, the composer said his goal was to premiere the work in Moscow in March of 2007 -- just before Easter in a year in which Catholics (using the Gregorian calendar) and the Orthodox (on the older Julian calendar) would celebrate the Paschal feast on the same day.

Hilarion wondered "if there might be a way for this work to then be performed in Rome and if I could help organize such a concert," said Moynihan. "We both knew this would be incredibly challenging. … But we did it and that night was like a miracle."

The Moscow premiere was on March 27 and, two nights later, the exhausted Russian choir and orchestra were in Rome for a performance attended by several Catholic Cardinals, as well as numerous students, scholars and dignitaries. One Orthodox participant was Metropolitan Kirill -- now the Russian patriarch.

Anyone probing the roots of the historic encounter between Patriarch Kirill and Pope Francis -- the first meeting of this kind between Rome and Moscow -- must study the years of cultural and musical contacts that built a bridge to this moment, said Moynihan, in an interview days before the Cuba summit. In the end, mutual concerns about the slaughter of Christians in Iraq and Syria made such a meeting an urgent necessity.