Pope Benedict has been a leader devoted to ecumenical efforts, according to a professor of Christian history and ecumenism at Fuller Theological Seminary, a Protestant school in Pasadena, Calif.

"I have appreciated his commitment to ecumenism," Cecil M. Robeck, Jr., who is also a minister in the Assemblies of God, an ecclesial community in the Pentecostal tradition, told CNA Feb. 19.

Robeck participated in the third inter-faith gathering at Assisi with Pope Benedict in 2011, and corresponded with him when he was still prefect of the Congregation for the Doctrine of the Faith.

After the warmth of John Paul II's pontificate, Robeck said there was some apprehension in the Protestant world that Pope Benedict might not "carry on in the way John Paul had."

Yet Pope Benedict "pretty much set everybody at ease by re-committing himself" to ecumenical efforts, Robeck said. He reported that in a July 2011 Pope Benedict greeted a Pentecostal group during an outdoor address, which "for me was a very affirming kind of thing."

"He's the first Pope we've heard make a verbal statements in his speech welcoming the Pentecostals, wishing us well and saying how important he felt the (Pentecostal-Catholic) dialogue was," Robeck remembered.

Robeck said Pope Benedict's three-book series on Jesus of Nazareth was warmly received by Pentecostals. "Benedict really won them over with his three volume series on the life of Jesus; that's a very important contribution he's made to the evangelical community."

"Here at Fuller that series is held up quite highly by faculty members," noted Robeck, and the series has helped pastors and church leaders to "recognize the level of his scholarship, and identify with the message he brings...they see him as providing really good comment on the New Testament."

Robeck noted his personal regard, as a Christian historian, for Pope Benedict's reflections on the Fathers of the Church. He also said the Pope's commitment to the new evangelization is "very important," and that "Benedict has been an important figure in helping all of our churches to rethink the question of evangelism."

Pope Benedict's efforts to reach out to various communities, particularly the Russian Orthodox and the Society of St. Pius X, has given Robeck "a great deal of hope that Benedict's concern about unity, is a real concern."

Robeck also noted that "Dominus Iesus," a declaration written in 2000 by Pope Benedict when he was Prefect of the Congregation for the Doctrine of the Faith, "really spoke to the concerns of evangelicals and Pentecostals by calling once again for a conformity to the 'middle,' with his reiteration of Jesus Christ as the only way, the truth and the life."

"Dominus Iesus," which emphasize the salvific universality of Christ and the Church, "was a very important document...very much appreciated by evangelicals and Pentecostals," Robeck said.

Pope Benedict's efforts at ecumenism were also praised by a Russian Orthodox bishop, Metropolitan Hilarion of Volokolamsk, who said his pontificate has seen a "positive dynamic" in Catholic-Russian Orthodox relations.

"He is a prominent theologian, who is well versed in the tradition of the Orthodox Church while having the sensitivity that makes it possible for him to build relations with Orthodox Church on (a) due level," the Metropolitan said Feb. 11.

He praised the Pope's staunch opposition to the "dictatorship of relativism" and said that his "traditionalism and conservatism...are of credit for millions of Christians, both Catholic and non-Catholic, who seek to preserve traditional Christian spiritual and moral values."

In 2009, Pope Benedict achieved a landmark in ecumenism and reconciliation with his apostolic constitution "Anglicanorum coetibus." This document allowed Anglican converts to join the Catholic Church in groups and preserve elements of their spiritual and liturgical heritage.

That initiative, as well as others, led Father John Zuhlsdorf, who writes an influential blog, to start calling  Benedict "the Pope of Christian Unity" in Oct., 2009.

Pope Benedict's efforts for Christian unity have not been solely outside the Catholic Church, but within it as well.

In 2007 he wrote a motu proprio "Summorum pontificum" which gave all priests the right to say the Mass as it was in 1962, prior to the Second Vatican Council. It recognized that Vatican II did not abrogate the previous liturgy, and helped to harmonize the Church with her past.

The Priestly Fraternity of Saint Peter, which is in full communion with the Pope and which celebrates the Roman rite as it was in 1962, said Pope Benedict, "a tireless apostle of Church unity....ever mindful of the restoration of the sacred, reconciled the Roman Church with its two-thousand year liturgical patrimony."

Pope Benedict also launched a series of doctrinal discussions between the Vatican and the Society of St. Pius X, a priestly fraternity founded in 1970 to form priests in response to supposed errors that crept into the Church following Vatican II. The discussions are currently at a stalemate, and the Vatican awaits a definitive response from the Society.

The Society said Feb. 11 that it "expresses its gratitude to (Pope Benedict) for the strength and the constancy that he has shown toward it in such difficult circumstances, and assures him of its prayers for the time that he wishes to devote from now on to recollection."

"Following its founder, Archbishop Marcel Lefebvre, the Society of Saint Pius X reaffirms its attachment to eternal Rome...and to the See of Peter."

"It prays that, under the inspiration of the Holy Spirit, the cardinals of the next conclave may elect the pope who, according to the will of God, will work for the restoration of all things in Christ."