The World Communion of Reformed Churches signed a declaration this week endorsing the 1999 Catholic-Lutheran agreement on how Christians might be worthy of salvation in the eyes of God.

“We know what our traditions, we know what our differences are, but we also know what unites us.”

A total of 40 percent of surveyed countries registered "high" or "very high" levels of overall restrictions, according to Pew Research Center’s annual study on global restrictions on religion.

Catholics and evangelicals must “continue to witness together to the Gospel and to continue on the road to full unity,” Francis said.

The week of prayer, Pope Francis said, urges Catholics and Lutherans to reconcile and "draw closer to one another anew through conversion."

The statement is expected to express remorse that the (Protestant) Church of England carried out so many acts of violence.