POPE BENEDICT XVI has officially stepped down as the head of the Roman Catholic Church.

The religious leader, who was elected Pope in 2005, left the Vatican by helicopter on Thursday (28Feb13) to the cheers of crowds outside the Apostolic Palace as the bells of St. Peter's Basilica rang throughout Vatican City.

He was transported to the papal summer retreat at Castel Gandolfo, where the pontiff, wearing his traditional white robes, stepped out onto a balcony for his last public appearance as Pope Benedict Xvi to address supporters who had gathered in the small Italian town to greet the new retiree.

He told the crowd, "Thank you for your friendship, for your affection... We will proceed forward for the good of the Church, for the good of the world... Thank you and good night, to everyone, thank you."

He also expressed his gratitude to followers in his final post on the official Papal Twitter.com account, writing: "Thank you for your love and support. May you always experience the joy that comes from putting Christ at the centre of your lives."

Pope Benedict Xvi had earlier bid farewell to each of the cardinals who will elect his successor and pledged to act with "unconditional reverence and obedience" towards the next Catholic leader.

He officially went into retirement at 8pm local time, when his title changed to pope emeritus.

The 85 year old shocked the world on 11 February (13) when he announced his plans to step down from the prestigious role due to poor health. He is the first head of the Catholic Church to retire from office in almost 600 years.

A new Pope is expected to be appointed in time for the annual Easter services in late March (13).