CASTEL GANDOLFO, Italy – Pope 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 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.