CASTEL GANDOLFO, Italy — Benedict XVI left the Catholic Church in unprecedented limbo on Thursday as he became the first pope in 600 years to resign, capping a tearful day of farewells that included an extraordinary pledge of obedience to his successor.
As bells tolled, two Swiss Guards standing at attention at the papal palace in Castel Gandolfo shut the thick wooden doors shortly after 8 p.m., symbolically closing out a papacy whose legacy will be most marked by the way it ended — a resignation instead of a death.
Benedict, who will spend his first two months of retirement inside the palace walls, leaves behind an eight-year term shaped by struggles to move the church beyond clerical sex abuse scandals and to reawaken Christianity in an indifferent world — efforts his successor will now have to take up.
For the time being, the governance of the Catholic Church shifts to Cardinal Tarcisio Bertone, the camerlengo, or chamberlain, who, along with the College of Cardinals, will guide the church and make plans for the conclave to elect the 266th leader of the world’s Catholics.
One of Bertone’s first acts was to lock the papal apartment inside the Vatican. In another task steeped in symbolism, he will ensure that Benedict’s fisherman’s ring and seal are destroyed.
On Benedict’s last day, the mood was vastly different inside the Vatican than at Castel Gandolfo. At the seat of the popes, Benedict’s staff tearfully bade the pontiff goodbye in scenes of dignified solemnity. A more lively atmosphere reigned in the countryside, with well-wishers jamming the hilltop town’s main square shouting ‘‘Viva il Papa!’’ (Long live the pope!) and wildly waving the yellow and white flags of the Holy See.
‘‘I am simply a pilgrim beginning the last leg of his pilgrimage on this Earth,’’ Benedict told the cheering crowd in his final public words as pope.
It was a remarkable bookend to a papacy that began on April 19, 2005, with a similarly meek speech delivered from the loggia overlooking St. Peter’s Square, where the newly elected Benedict said he was but a ‘‘simple humble worker in the vineyard of the Lord.’’
Over eight years, Benedict tried to set the church on a more traditional course, convinced that all the ills afflicting it — sexual abuse, dwindling numbers of priests, and empty pews — were a result of a misreading of the reforms of the Second Vatican Council.
His successor is likely to follow in his footsteps given that the vast majority of the 115 cardinals who will elect the next pope were appointed by Benedict himself and share his conservative bent.
For the most part, his cardinals have said they understood Benedict’s decision. But Sydney Cardinal George Pell caused a stir Thursday by saying it was ‘‘slightly destabilizing’’ — a rare critique.
Benedict’s journey into retirement began with a final audience with his cardinals Thursday morning, where he sought to defuse concerns about his future role and the possible conflicts arising from the peculiar situation of having both a reigning pope and a retired one living side-by-side inside the Vatican.
‘‘Among you is also the future pope, whom I today promise my unconditional reverence and obedience,’’ Benedict told the cardinals.
Benedict’s decision to live at the Vatican in retirement, be called ‘‘emeritus pope’’ and ‘‘Your Holiness’’ rather than ‘‘Joseph Ratzinger,’’ and wear the white cassock associated with the papacy has deepened concerns about the shadow he might cast over the next papacy.
Benedict has tried to address those worries over the past two weeks, saying that once retired, he would be ‘‘hidden from the world’’ and living a life of prayer. On Thursday he took a step further with his own public pledge to place himself entirely under the authority of the new pope.