Catholic and Protestant congregations will celebrate their belief in Jesus' resurrection on the same day as Orthodox churches in 2010 and 2011 because of a coincidence in the Julian and Gregorian calendars. The common holiday has happened three times this decade. But the World Council of Churches says consensus is emerging that these should not just be occasional occurrences.

At a recent meeting in Lviv, Ukraine, theologians representing nearly the breadth of Christianity agreed in principle on a strategy for all the faithful to continue observing their feast together.

"It's not a problem of principle, of dogma or of doctrine," said Juan Michel, spokesman for the council, whose 350 Protestant, Orthodox and other churches represent more than 560 million Christians. It cooperates with the Roman Catholic Church, which is not a member.

"It's more of a pastoral issue for some churches," said Michel. "There are concerns how the faithful will feel if there is a change in the traditional way of calculating the date."