Russian President Vladimir Putin visits Pope John Paul this week to gently nudge the Orthodox and Catholic churches toward improving ties soured by a decade of post-Communist suspicions.
But his efforts may prove too late for John Paul, a key figure in the downfall of communism in eastern Europe, whose failing health could prevent him from fulfilling his dream of visiting Moscow unless a possibility comes soon.
Attempts to promote dialogue between the Vatican and a reinvigorated Russian Orthodox Church have made little progress.
Orthodox Patriarch Alexiy II has made a visit by the Pontiff contingent on resolving complaints that Catholics are both poaching congregations and provoking disputes over property in western Ukraine -- home to six million eastern-rite Catholics.
Catholic leaders deny proselytizing and say new dioceses and the naming of new bishops are strictly to serve the faithful.
Putin, who meets the Pope on Wednesday while in Rome for a Russia-European Union summit, said his second visit to the Vatican was aimed at overcoming divisions within Christianity.
"I therefore see my objective not in helping to get the pope to Russia but in helping steps toward unity. And naturally this is possible only if there is an understanding between churches," he told Italian journalists before leaving.
"For Russia it is even more important because it represents a further step toward integration with Europe. But we want to integrate with the West without losing out culture, our faith or our identity. We must tread very carefully on this path...
"The pope is a wise and intelligent person -- we have met before -- and I am certain we will have plenty to talk about."
John Paul sees reconciliation with Orthodoxy, separated from the Catholic faith since the Great Schism of 1054, as a primary objective of his papacy. He first visited an Orthodox country, Romania, in 1999, and has since toured many ex-Soviet states, but Russia remains his prized destination.
ORTHODOX AGREEMENT NEEDED FOR PAPAL VISIT
Catholic sources expect Putin to renew the standing invitation to visit extended by his predecessors, Boris Yeltsin and Soviet leader Mikhail Gorbachev. But no visit is possible without agreement from Alexiy and the Orthodox hierarchy.
Vatican sources say such a trip is so important to the pope, who suffers from Parkinson's disease, that he would be willing to make a brief, symbolic visit even in his current health.
An attempt in 1997 to stage a meeting between John Paul and Alexiy collapsed and top-level relations remain stalled.
"For the moment, we cannot speak of any significant shift in official relations between the Russian Orthodox Church and the Vatican," Alexiy told the daily Izvestia last week.
"The Vatican is still pursuing its expansion into areas of the former Soviet Union where the Orthodox Church is the biggest Christian church. This cannot but generate serious concern."
Problems have spilled over into other ex-Soviet states. Georgia postponed signature of a pact with the Vatican in September after objections from the local Orthodox church.
Catholic priests in Moscow, many of them originating from Poland, say day-to-day working conditions have improved since a year ago when many were subject to problems with visas and working papers and some incidents of harassment were reported.
Church activists say tension has eased in Ukraine a decade after eastern-rite Catholics emerging from a Soviet-era ban on their faith were locked in conflicts to reclaim seized churches.
But a general improvement in ties would take time.
Vatican sources say disagreements run deep and change was unlikely with candidates to succeed the elderly and ailing Alexiy unlikely to take any initiatives.
"We say there should be full freedom of religion. They say that everyone who is born Russian is automatically part of the Orthodox Church," said one source. "No one wants to be the one to take off their hat to the Catholics first." (Additional reporting by Philip Pullella in Rome)