VATICAN CITY (RNS)-- Pope John Paul II welcomed the leader of the world's 250million Orthodox Christians to the Vatican on Tuesday (June 29) with anappeal for a "leap forward" in relations between the long-divided Catholicand Orthodox churches. Ecumenical Patriarch Bartholomew I came to Rome at the pope's invitationto mark the 40th anniversary of the historic meeting between Pope Paul VIand Patriarch Atenagora I in Jerusalem that opened the way to dialoguebetween the churches separated by the "great schism" of 1054. "The memory of that meeting favors a leap forward in dialogue and in thestrengthening of mutual fraternal relations," John Paul told Bartholomew ata private audience Tuesday morning. He asked specifically for the urgentresumption of theological dialogue by a joint Catholic-Orthodox commission. The pope acknowledged, however, that the memory of such events as the13th century sack of Constantinople during the Fourth Crusade still impededunity. Bartholomew is headquartered in Istanbul (formerly Constantinople)and is considered the first among equals of Orthodox hierarchs. Bartholomew agreed that dialogue "has fluctuations because of thedifficulties accumulated by the history of the long division." But he calledit the "responsibility and the duty" of both churches to seek unity withoutlosing hope. The white-bearded patriarch later joined the pope in the early eveningat a Mass in St. Peter's Square attended by some 15,000 pilgrims tocelebrate the Solemnity of the Apostles Sts. Peter and Paul. Bartholomew,wearing a purple stole embroidered in gold with biblical scenes, sat withJohn Paul during part of the Mass, but separately during Communion. Together they recited the Nicene-Constantinopolitan Creed used byByzantine churches, and each delivered a homily in Italian. A Greek Orthodoxchoir from Athens sang and the Gospel was read in Latin and Greek. Both the pope and the patriarch called unity a gift of God. "Yourholiness," Bartholomew said, "we dream with joy of the day in which all theobstacles to full communion will be removed, and we pray continually thatthat day may not be long in coming." John Paul reiterated the "irrevocable" commitment of the Catholic Churchto dialogue. "I want today to express the wish that all Christiansintensify, each in his own way, the efforts to speed the day in which thedesire of the Lord `that they may be one' will be fully realized," he said. The ailing 84-year-old pope nodded in agreement as he listened toBartholomew, 64, and applauded at the end of the homily. When it was histurn, he spoke relatively clearly but with obvious effort. During the Mass John Paul bestowed the pallium, a band of woolsymbolizing the bond of union with the pope, on 44 new archbishops,including Cardinal Justin Rigali of Philadelphia and Archbishops SeanO'Malley of Boston, Henry Mansell of Hartford, Conn., Raymond Burke of St.Louis, Mo., and Raymond Roussin of Vancouver, Canada. The visit was the third that Bartholomew has made to Rome since he waselected the 270th archbishop of Constantinople and ecumenical patriarch in1991. He led an Orthodox delegation that traditionally attends the feast ofthe patrons of the Roman Catholic Church. A Vatican delegation traditionallyvisits Fanar in Turkey for the feast of the Orthodox patron St. Andrew onNov. 30. Earlier this month, John Paul backed away from plans to establish aCatholic Patriarchate in predominantly Orthodox Ukraine after Bartholomewwarned it could mean the end of dialogue. John Paul recalled the "blessed meeting" between Paul and Atenagora in1964, but said he knew that the memory of "sad events of past history"weighed on efforts to end the Catholic-Orthodox schism. "In particular," he said, "in these circumstances we cannot forget whathappened in the month of April in the year 1204. An army, which left torecover the Holy Land for Christianity, headed toward Constantinople to takeand sack it, spilling the blood of brothers in faith." During a visit to Athens in May 2001, the pope offered a formal apologyfor this and other "deep wounds" that Roman Catholics have caused to "theirOrthodox brothers and sisters" over the last millennium. Bartholomew said inApril that he gave his "pardon" to Catholics for the sack of Constantinople. Asking for the resumption of dialogue by the mixed commission oftheologians, which he described as "an important instrument," John Paulsaid, "I am convinced, in fact, of much urgency." "It is my will and that of my collaborators to avail ourselves of everymeans to feed the spirit of reciprocal welcome and comprehension in faith tothe Gospel and to the common apostolic traditions," the pope said.