In the second joint declaration they have signed since May, Pope Francis and Patriarch Bartholomew reaffirmed their shared desire for full Christian unity, as well as their concerns for the Middle East.

"We, Pope Francis and Ecumenical Patriarch Bartholomew I, express our profound gratitude to God for the gift of this new encounter," the declaration, signed by the two on Nov. 30, read.

In addition, the two expressed their "sincere and firm resolution, in obedience to the will of our Lord Jesus Christ, to intensify our efforts to promote the full unity of all Christians, and above all between Catholics and Orthodox."

The signing of the declaration fell at the end of the Divine Liturgy celebrated in Istanbul's Orthodox cathedral of St. Gregory on Nov. 30 in honor of the feast of St. Andrew, patron and founder of the Orthodox churches.

It also fell on the final day of Pope Francis' three-day apostolic voyage to Turkey, which was made largely upon the invitation of the patriarch to participate in the festivities for St. Andrew's feast.

Pope Francis and Patriarch Bartholomew pointed to the Joint International Commission, instituted exactly 35 years ago by Ecumenical Patriarch Dimitrios and St. John Paul II.

The commission, they noted, "is currently dealing with the most difficult questions that have marked the history of our division and that require careful and detailed study," and encouraged all their faithful to join them in praying "that all may be one, that the world may believe."

Attention was then drawn to the current situation unfolding in the Middle East, particularly Syria and Iraq.

"We are united in the desire for peace and stability and in the will to promote the resolution of conflicts through dialogue and reconciliation," they said, and encouraged all who are in positions of responsibility to strengthen their commitment to assist peoples affected by violence, and to enable them to stay in their land.

Bartholomew and Francis lamented the tragic situation of the many who have been forced to leave their homes due to violence, as well as the lack of respect for the value of human life and the indifference of many in front of the situation.

"We cannot resign ourselves to a Middle East without Christians, who have professed the name of Jesus there for two thousand years," the declaration read, and affirmed that they share in an "ecumenism of suffering" for all those affected.

They said that just as the blood of the martyrs served as the seed of fertility for the growth of the initial Church, so too will the suffering of modern Christians serve as a key tool in building ecumenical unity.

In addition the Pope and the Patriarch also called on the world to foster solidarity and a greater dialogue with Islam that is based on friendship and respect.

"Muslims and Christians are called to work together for the sake of justice, peace and respect for the dignity and rights of every person, especially in those regions where they once lived for centuries in peaceful coexistence and now tragically suffer together the horrors of war," they said.

As Christian leaders, the two called on all religious leaders of the world to make every possible effort to strengthen interreligious dialogue in order to build a culture of peace. They offered particular prayers for peace in Ukraine, which has a rich historical Christian presence.

They closed the declaration by praying that all churches throughout the world would be "untiring witnesses to the love of God," and asked that the Lord grant the gifts of peace "in love and unity" to all of humanity.

In addition to signing their second joint declaration, Pope Francis and Patriarch Bartholomew have made several other significant gestures of friendship, including a shared moment of prayer in Jerusalem's Church of the Holy Sepulcher during the Roman Pontiff's trip to the Holy Land in May, as well as at the Vatican in June for an invocation for peace between Israel and Palestine.

During last night's prayer vigil anticipating the feast of St. Andrew, they shared another historic moment when Pope Francis asked the patriarch for a favor: "to bless me and the Church of Rome."

He then bowed to receive the blessing and was embraced by the Patriarch, who traced the sign of the cross on the pontiff's head and kissed it.