Pope Benedict XVI has officially stepped down on Thursday after nearly eight years in office.

Pope Benedict XVI has officially stepped down on Thursday after nearly eight years in office.

The pontiff, aged 85, the first pontiff to do so in six centuries. He will be known as Benedict XVI, pope emeritus, from now on.

The landmark resignation took effect three hours after the pope left the Vatican and flew by helicopter to his retreat at Castel Gandolfo, a summer residence south of Rome.

A crowd of well-wishers stood before the gates of the Castel Gandolfo residence as the Swiss Guards, the soldiers who traditionally protect the pope, saluted and closed the doors of the palazzo on the stroke of 8 p.m. local time (1900 GMT), symbolically closing out the papacy.

The Swiss Guards have now gone off duty, and the protection of Benedict has been taken over by Vatican police.

Addressing the cheering crowd from a window at the summer retreat, he said that he would soon no longer be the leader of the Catholic Church, rather "a pilgrim who begins the last stop of his pilgrimage."