Pope Benedict XVI officially retired on Thursday after eight years as leader of the Catholic Church. 
 
 The Pope has given an emotional last general audience before stepping down as pontiff, during which he spoke of "difficult moments". 
 
 Benedict XVI told the 150,000-strong crowd in St Peter's Square in the Vatican City, the papal enclave in Rome, that he had been aware of the "gravity" of his decision to step down, but it was for the good of the Church. 
 
 The Pope stunned the Roman Catholic Church when he announced on February 11 he no longer had the mental or physical strength to carry on in the role. 
 
 He will officially stand aside on Thursday evening, the first pope to do so in 600 years. 
 
 As he arrived in the square, Benedict greeted pilgrims and waved to the tens of thousands of people who had gathered to bid him farewell. 
 
 He was driven around in an open-sided vehicle, surrounded by bodyguards. At one point he stopped to kiss a baby who had been handed up to him by his secretary. 
 
 The crowd fell silent as he started to speak. 
 
 The Pope began by saying he would keep the faithful in his prayers and has "great trust" in the future of the Church. 
 
 Many in the audience chanted "Benedetto" 
 
 "To love the Church means also to have the courage to take difficult, painful decisions, always keeping the good of the Church in mind, not oneself," Benedict said to thundering applause. 
 
 He recalled that when he was elected Pope on April 19, 2005, he questioned if God truly wanted it "It's a great burden that you've placed on my shoulders," he recalled telling God. 
 
 He said his papacy had faced joy, but also had undergone "difficult moments". He said that during his time as leader of the 1.2 billion Roman Catholics around the world, he had negotiated "turbulent seas". 
 
 Drawing on a Biblical analogy, he said: "The Lord gave us days of sun and of light breeze, days in which the fishing was good. There were also moments when there were stormy waters and headwinds. 
 
 "But I always knew that God was in that boat and I always knew that the boat of the Church is not mine, is not ours, but is his and he will not let it sink." 
 
 Pope Benedict said he was aware of the "gravity and novelty" of his decision to resign and would accompany the Church in prayer even after his resignation. 
 
 He told the crowd he was not "coming down from the Cross", but would remain in the service of the Church through prayer. 
 
 He asked the faithful to pray for the cardinals as they faced a weighty task choosing his successor and for whoever they chose. 
 
 After he had finished speaking, the crowd gave a rousing round of applause that lasted nearly a minute. 
 
 He went on to say a few extra words in other languages, one of which was English. 
 
 Tens of thousands of people, some toting banners saying "Thank you!" had earlier began filling St Peter's Square in preparation for his appearance. 
 
 Many of the cardinals who will choose the next Pope were among those listening. 
 
 Later it was revealed that the Pope had expressed his gratitude for the welcome he received during his visit to Britain in 2010 and for the prayers of British Catholics since he decided to step down. 
 
 A letter written on his behalf by Vatican official Archbishop Giovanni Angelo Becciu thanked his UK-based followers. 
 
 On Thursday morning, he will bid farewell to his cardinals who will begin a series of meetings to determine his successor. 
 
 At precisely 8pm (Rome time) the villa gates at Castel Gandolfo will close and the Swiss Guard will withdraw - a symbol that Pope Benedict XVI's papacy is over. 
 
 Once he completes his resignation, the Pope will leave the Vatican and fly by helicopter to the papal summer residence at Castel Gandolfo, south of Rome, until renovations have been completed on a monastery inside the Vatican walls. 
 
 Benedict will then be known as Emeritus Pope and wear a simple white cassock and brown shoes rather than his trademark red loafers. 
 
 The Pope will live out the rest of his days in the new monastery in prayer and meditation. 
 
 A total of 115 "cardinal electors" are scheduled to take part after one said he was too sick and British cardinal Keith O'Brien said he would not be taking part after allegations of inappropriate behaviour regarding four priests emerged at the weekend. 
 
 The Pope named the Archbishop of Glasgow as temporary successor to Cardinal O'Brien in one of his last acts as head of the Catholic Church. 
 
 Philip Tartaglia will govern the Roman Catholic Archdiocese of St Andrews and Edinburgh until a permanent successor is appointed, but will not be able to attend the conclave. 
 
 The date for the conclave - when eligible cardinals vote in secret in the Sistine Chapel - has yet to be announced, but must take place within 20 days of the Pope's last day. 
 
 Another of the Pope's last acts was to announce that the Turin Shroud will be put on display again for one day on March 30. It has only been shown five times in the last 100 years. ||||| 1 of 25. Pope Benedict XVI waves to the faithful as he arrives in St Peter's Square to hold his last general audience at the Vatican February 27, 2013. The weekly event which would normally be held in a vast auditorium in winter, but has been moved outdoors to St. Peter's Square so more people can attend. The pope has two days left before he takes the historic step of becoming the first pontiff in some six centuries to step down instead of ruling for life. 
 
 VATICAN CITY (Reuters) - Pope Benedict bid an emotional farewell at his last general audience on Wednesday, acknowledging the "rough seas" that marked his papacy "when it seemed that the Lord was sleeping." 
 
 In an unusually public outpouring for such a private man, he alluded to some of the most difficult times of his papacy, which was dogged by sex abuse scandals, leaks of his private papers and reports of infighting among his closest aides. 
 
 "Thank you, I am very moved," Benedict told a cheering crowd of more than 150,000 people in St Peter's Square a day before he becomes the first pope to step down in some six centuries. 
 
 He said he had great trust in the Church's future, that his abdication was for the good of the Church and asked for prayers for cardinals choosing his successor at a time of crisis. 
 
 The Vatican said the address, repeatedly interrupted by applause and cries of "Benedict, Benedict" - was the last by the pope, who as of Thursday evening will have the title "pope emeritus." 
 
 "There were moments of joy and light but also moments that were not easy ... there were moments, as there were throughout the history of the Church, when the seas were rough and the wind blew against us and it seemed that the Lord was sleeping," he said. 
 
 When he finished the crowd, which spilled over into surrounding streets and included many of the red-hatted cardinals who will elect his successor in a closed doors conclave next month, stood to applaud. 
 
 "I took this step in the full knowledge of its gravity and rarity but with a profound serenity of spirit," he said, as people in the crowd wave supportive banners and national flags. 
 
 Loving the Church meant, "having the courage to take difficult and anguished choices, always having in mind the good of the church and not oneself," he said. 
 
 The pope says he is too old and weak to continue leading a Church beset by crises over child abuse by priests and a leak of confidential Vatican documents showing corruption and rivalry among Vatican officials. 
 
 He said he was not "coming down from the cross" but would serve the Church through prayer. 
 
 Some of those who have faulted Benedict for resigning have pointed to the late Pope John Paul, who said he would "not come down from the cross" despite his bad health because he believed his suffering could inspire others. 
 
 CHURCH CRISIS 
 
 Many Catholics and even some close papal aides were stunned by his decision on February 11 and concerned about the impact it will have on a Church torn by divisions. 
 
 Most in the square were supportive of Benedict, an increasingly frail figure in the last months of his papacy. 
 
 "He did what he had to do in his conscience before God," said Sister Carmel, from a city north of Rome, who came to the capital with her fellow nuns and members of her parish. 
 
 "This is a day in which we are called to trust in the Lord, a day of hope," she said. "There is no room for sadness here today. We have to pray, there are many problems in the Church but we have to trust in the Lord." 
 
 Not everyone agreed. 
 
 "He was a disaster. It's good for everyone that he resigned," said Peter McNamara, 61, an Australian of Irish descent who said he had come to the square "to witness history". 
 
 The pope, a theologian and professor, never felt truly comfortable with the weight of the papacy and many Catholics feel that, although he was a towering Church figure, perhaps the cardinals should have chosen someone else in 2005. 
 
 "It was clear from the start that he was more at home in a library," said Carla Manton, 65. "A very good man but he realized in his heart that this was the right thing to do for himself and the Church and now he will pray, he will pray for all of us." 
 
 Benedict will move to the papal summer residence south of Rome on Thursday night and later to a convent in the Vatican. 
 
 He will lay aside the red "shoes of the fisherman" that have been part of his papal attire and wear brown loafers given to him by shoemakers during a trip to Leon, Mexico last year. He will wear a "simple white cassock", the Vatican said. 
 
 His lead seal and his ring of office, known as the "ring of the fisherman", will be destroyed according to Church rules, just as if he had died. 
 
 The Vatican said on Tuesday that the pope was sifting through documents to see which will remain in the Vatican and go into the archives of his papacy and which "are of a personal nature and he will take to his new residence". 
 
 Among the documents left for the next pope will be a confidential report by three cardinals into the "Vatileaks" affair last year when Benedict's former butler revealed private papers showing corruption and in-fighting inside the Vatican. 
 
 The new pope will inherit a Church marked by Vatileaks and child abuse scandals involving priests in Europe and the United States, both of which may have weighed on Benedict's decision. 
 
 On Thursday, he will greet cardinals in Rome. That afternoon he will fly by helicopter to the papal summer retreat at Castel Gandolfo, a 15-minute journey. In his last appearance as pope, he will greet residents and well-wishers in a small square. 
 
 At 8 p.m. the Swiss Guards who stand as sentries at the residence will march off in a sign that the papacy is vacant. 
 
 Benedict changed Church rules so that cardinals who start pre-conclave meetings on Friday could begin the conclave earlier than the 15 days after the papacy becomes vacant prescribed by the previous law. 
 
 The Vatican appears to be aiming to have a new pope elected by mid-March and installed before Palm Sunday on March 24 so he can preside at Holy Week services leading to Easter. 
 
 Cardinals have begun informal consultations by phone and email in the past two weeks since Benedict said he was quitting.
– It's Benedict XVI's penultimate day of pontificating, and tens of thousands of the faithful gathered in St. Peter's Square for an emotional farewell in which the pope recalled the "great burden" God had given him in 2005 and noted that his papacy had weathered difficult moments when "it seemed like the Lord was sleeping." But there were also "days of sun and light," Sky News reports. Benedict said he wasn't "coming down from the cross," but that "to love the church means also to have the courage to take difficult, painful decisions, always keeping the good of the church in mind, not oneself." He recalled "turbulent seas," but said, "I always knew that the boat of the church is not mine, is not ours, but is his and he will not let it sink." The Vatican estimates the crowd hit 150,000, far exceeding the 50,000 who requested tickets for the pope's last general audience, reports Reuters. The position will officially become vacant at 8pm tomorrow, after which the "pope emeritus" will cast aside his red shoes, switch to plain brown loafers, and head for the papal summer residence until renovations to a monastery inside the Vatican are complete.