CASTEL GANDOLFO, — Benedict XVI left the Catholic Church in unprecedented limbo 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 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 now, governance of the church shifts to Cardinal Tarcisio Bertone, the chamberlain, who along with the College of Cardinals will guide the church and make plans to elect the 266th leader of 1.2 billion 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.